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vmemu
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porting project to support linux... std::vector<std::uint8_t> module_data is not page aligned and so qemu shits itself. going to need to re-write some stuff...

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dev
IDontCode 2 years ago
parent 1385a7cfe2
commit 0549d95b5d
6 changed files with 1505 additions and 1574 deletions
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2
dependencies/vmprofiler vendored

@ -1 +1 @@
Subproject commit 1b6875d18825529907289bc87990fed5d99e7f96
Subproject commit dd7d3777ad10373d0eeb23c118e4bdcfc7464494

96
include/unpacker.hpp
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@ -1,14 +1,14 @@
#pragma once
#include <functional>
#include <Zydis/Zydis.h>
#include <unicorn/unicorn.h>
#include <Zydis/Zydis.h>
#include <atomic>
#include <fstream>
#include <functional>
#include <map>
#include <nt/image.hpp>
#include <vector>
#include <xtils.hpp>
#include <vmprofiler.hpp>
#define PAGE_4KB 0x1000
#define STACK_SIZE PAGE_4KB * 512
@ -27,46 +27,50 @@
#define MOV_RAX_0_SIG "\x48\xB8\x00\x00\x00\x00\x00\x00\x00\x00"
#define MOV_RAX_0_MASK "xxxxxxxxxx"
static_assert( sizeof MOV_RAX_0_SIG == sizeof MOV_RAX_0_MASK, "signature and mask sizes are wrong..." );
namespace engine
{
class unpack_t
{
public:
explicit unpack_t( const std::vector< std::uint8_t > &bin );
~unpack_t( void );
bool init( void );
bool unpack( std::vector< std::uint8_t > &output );
private:
using iat_hook_t = std::function< void( uc_engine *, unpack_t * ) >;
uc_engine *uc_ctx;
std::vector< uint8_t > bin, map_bin;
std::vector< uc_hook * > uc_hooks;
std::uintptr_t img_base, img_size, heap_offset, pack_section_offset;
win::image_t<> *win_img;
static void local_alloc_hook( uc_engine *, unpack_t * );
static void local_free_hook( uc_engine *, unpack_t * );
static void load_library_hook( uc_engine *, unpack_t * );
static void uc_strcpy( uc_engine *, char *buff, std::uintptr_t addr );
static bool iat_dispatcher( uc_engine *uc, uint64_t address, uint32_t size, unpack_t *unpack );
static bool unpack_section_callback( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,
unpack_t *unpack );
static bool code_exec_callback( uc_engine *uc, uint64_t address, uint32_t size, unpack_t *unpack );
static void invalid_mem( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,
unpack_t *unpack );
std::vector< std::uintptr_t > loaded_modules;
std::map< std::string, std::pair< std::uint32_t, iat_hook_t > > iat_hooks = {
{ "LocalAlloc", { LOCAL_ALLOC_VECTOR, &local_alloc_hook } },
{ "LocalFree", { LOCAL_FREE_VECTOR, &local_free_hook } },
{ "LoadLibraryA", { LOAD_LIBRARY_VECTOR, &load_library_hook } } };
};
} // namespace engine
static_assert(sizeof MOV_RAX_0_SIG == sizeof MOV_RAX_0_MASK,
"signature and mask sizes are wrong...");
namespace engine {
class unpack_t {
public:
explicit unpack_t(const std::vector<std::uint8_t> &bin);
~unpack_t(void);
bool init(void);
bool unpack(std::vector<std::uint8_t> &output);
private:
using iat_hook_t = std::function<void(uc_engine *, unpack_t *)>;
uc_engine *uc_ctx;
std::vector<uint8_t> bin, map_bin;
std::vector<uc_hook *> uc_hooks;
std::uintptr_t img_base, img_size, heap_offset, pack_section_offset;
win::image_t<> *win_img;
static void local_alloc_hook(uc_engine *, unpack_t *);
static void local_free_hook(uc_engine *, unpack_t *);
static void load_library_hook(uc_engine *, unpack_t *);
static void uc_strcpy(uc_engine *, char *buff, std::uintptr_t addr);
static bool iat_dispatcher(uc_engine *uc, uint64_t address, uint32_t size,
unpack_t *unpack);
static bool unpack_section_callback(uc_engine *uc, uc_mem_type type,
uint64_t address, int size, int64_t value,
unpack_t *unpack);
static bool code_exec_callback(uc_engine *uc, uint64_t address, uint32_t size,
unpack_t *unpack);
static void invalid_mem(uc_engine *uc, uc_mem_type type, uint64_t address,
int size, int64_t value, unpack_t *unpack);
std::map<std::string, std::uintptr_t> loaded_modules;
std::map<std::string, std::pair<std::uint32_t, iat_hook_t> > iat_hooks = {
{"LocalAlloc", {LOCAL_ALLOC_VECTOR, &local_alloc_hook}},
{"LocalFree", {LOCAL_FREE_VECTOR, &local_free_hook}},
{"LoadLibraryA", {LOAD_LIBRARY_VECTOR, &load_library_hook}}};
};
} // namespace engine

90
include/vmemu_t.hpp
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#pragma once
#include <unicorn/unicorn.h>
#include <atomic>
#include <nt/image.hpp>
#include <vmprofiler.hpp>
@ -10,49 +11,46 @@
#define STACK_BASE 0xFFFF000000000000
#define IAT_VECTOR_TABLE 0xFFFFF00000000000
namespace vm
{
inline bool g_force_emu = false;
class emu_t
{
struct cpu_ctx_t
{
std::uintptr_t rip;
uc_context *context;
std::uint8_t stack[ STACK_SIZE ];
};
struct code_block_data_t
{
vm::instrs::code_block_t code_block;
std::shared_ptr< cpu_ctx_t > cpu_ctx;
std::shared_ptr< vm::ctx_t > g_vm_ctx;
};
public:
explicit emu_t( vm::ctx_t *vm_ctx );
~emu_t();
bool init();
bool get_trace( std::vector< vm::instrs::code_block_t > &code_blocks );
private:
std::uintptr_t img_base, img_size;
uc_hook code_exec_hook, invalid_mem_hook, int_hook;
uc_engine *uc_ctx;
vm::ctx_t *g_vm_ctx;
code_block_data_t *cc_block;
std::vector< std::uintptr_t > vip_begins;
std::vector< code_block_data_t > code_blocks;
std::map< std::uintptr_t, std::shared_ptr< vm::ctx_t > > vm_ctxs;
uc_err create_entry( vmp2::v2::entry_t *entry );
static void int_callback( uc_engine *uc, std::uint32_t intno, emu_t *obj );
static bool code_exec_callback( uc_engine *uc, uint64_t address, uint32_t size, emu_t *obj );
static void invalid_mem( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,
emu_t *obj );
};
} // namespace vm
namespace vm {
inline bool g_force_emu = false;
class emu_t {
struct cpu_ctx_t {
std::uintptr_t rip;
uc_context *context;
std::uint8_t stack[STACK_SIZE];
};
struct code_block_data_t {
vm::instrs::code_block_t code_block;
std::shared_ptr<cpu_ctx_t> cpu_ctx;
std::shared_ptr<vm::ctx_t> g_vm_ctx;
};
public:
explicit emu_t(vm::ctx_t *vm_ctx);
~emu_t();
bool init();
bool get_trace(std::vector<vm::instrs::code_block_t> &code_blocks);
private:
std::uintptr_t img_base, img_size;
uc_hook code_exec_hook, invalid_mem_hook, int_hook;
uc_engine *uc_ctx;
vm::ctx_t *g_vm_ctx;
code_block_data_t *cc_block;
std::vector<std::uintptr_t> vip_begins;
std::vector<code_block_data_t> code_blocks;
std::map<std::uintptr_t, std::shared_ptr<vm::ctx_t> > vm_ctxs;
uc_err create_entry(vmp2::v2::entry_t *entry);
static void int_callback(uc_engine *uc, std::uint32_t intno, emu_t *obj);
static bool code_exec_callback(uc_engine *uc, uint64_t address, uint32_t size,
emu_t *obj);
static void invalid_mem(uc_engine *uc, uc_mem_type type, uint64_t address,
int size, int64_t value, emu_t *obj);
};
} // namespace vm

711
src/main.cpp
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#include "unpacker.hpp"
#include "vmemu_t.hpp"
#include <cli-parser.hpp>
#include <fstream>
#include <iostream>
#include <xtils.hpp>
int __cdecl main( int argc, const char *argv[] )
{
argparse::argument_parser_t parser( "VMEmu", "VMProtect 2 VM Handler Emulator" );
parser.add_argument().name( "--vmentry" ).description( "relative virtual address to a vm entry..." );
parser.add_argument().name( "--bin" ).description( "path to unpacked virtualized binary..." );
parser.add_argument().name( "--out" ).description( "output file name..." );
parser.add_argument().name( "--unpack" ).description( "unpack a vmp2 binary..." );
parser.add_argument().names( { "-f", "--force" } ).description( "force emulation of unknown vm handlers...\n" );
parser.add_argument()
.name( "--emuall" )
.description( "scan for all vm enters and trace all of them... this may take a few minutes..." );
parser.add_argument()
.name( "--locateconst" )
.description( "scan all vm enters for a specific constant value...\n" );
parser.enable_help();
auto result = parser.parse( argc, argv );
if ( result )
{
std::printf( "[!] error parsing commandline arguments... reason = %s\n", result.what().c_str() );
return -1;
}
if ( parser.exists( "help" ) )
{
parser.print_help();
return 0;
}
auto umtils = xtils::um_t::get_instance();
vm::g_force_emu = parser.exists( "force" );
if ( !parser.exists( "unpack" ) && parser.exists( "vmentry" ) && parser.exists( "bin" ) && parser.exists( "out" ) )
{
const auto module_base = reinterpret_cast< std::uintptr_t >(
LoadLibraryExA( parser.get< std::string >( "bin" ).c_str(), NULL, DONT_RESOLVE_DLL_REFERENCES ) );
if ( !module_base )
{
std::printf( "[!] failed to open binary file...\n" );
return -1;
}
#include "unpacker.hpp"
#include "vmemu_t.hpp"
const auto vm_entry_rva = std::strtoull( parser.get< std::string >( "vmentry" ).c_str(), nullptr, 16 );
const auto image_base = umtils->image_base( parser.get< std::string >( "bin" ).c_str() );
const auto image_size = NT_HEADER( module_base )->OptionalHeader.SizeOfImage;
int __cdecl main(int argc, const char *argv[]) {
argparse::argument_parser_t parser("VMEmu",
"VMProtect 2 VM Handler Emulator");
parser.add_argument()
.name("--vmentry")
.description("relative virtual address to a vm entry...");
parser.add_argument()
.name("--bin")
.description("path to unpacked virtualized binary...")
.required(true);
parser.add_argument()
.name("--out")
.description("output file name...")
.required(true);
parser.add_argument().name("--unpack").description("unpack a vmp2 binary...");
parser.add_argument()
.names({"-f", "--force"})
.description("force emulation of unknown vm handlers...");
parser.add_argument()
.name("--emuall")
.description(
"scan for all vm enters and trace all of them... this may take a few "
"minutes...");
parser.enable_help();
auto result = parser.parse(argc, argv);
if (result) {
std::printf("[!] error parsing commandline arguments... reason = %s\n",
result.what().c_str());
return -1;
}
if (parser.exists("help")) {
parser.print_help();
return 0;
}
vm::util::init();
vm::g_force_emu = parser.exists("force");
std::vector<std::uint8_t> module_data, tmp, unpacked_bin;
if (!vm::util::open_binary_file(parser.get<std::string>("bin"),
module_data)) {
std::printf("[!] failed to open binary file...\n");
return -1;
}
auto img = reinterpret_cast<win::image_t<> *>(module_data.data());
auto image_size = img->get_nt_headers()->optional_header.size_image;
tmp.resize(image_size);
std::memcpy(tmp.data(), module_data.data(), 0x1000);
std::for_each(img->get_nt_headers()->get_sections(),
img->get_nt_headers()->get_sections() +
img->get_nt_headers()->file_header.num_sections,
[&](const auto &section_header) {
std::memcpy(tmp.data() + section_header.virtual_address,
module_data.data() + section_header.ptr_raw_data,
section_header.size_raw_data);
});
const auto module_base = reinterpret_cast<std::uintptr_t>(tmp.data());
const auto image_base = img->get_nt_headers()->optional_header.image_base;
std::printf("> image base = %p, image size = %p, module base = %p\n",
image_base, image_size, module_base);
if (!image_base || !image_size || !module_base) {
std::printf("[!] failed to open binary on disk...\n");
return -1;
}
if (parser.exists("vmentry")) {
const auto vm_entry_rva =
std::strtoull(parser.get<std::string>("vmentry").c_str(), nullptr, 16);
std::vector<vm::instrs::code_block_t> code_blocks;
vm::ctx_t vmctx(module_base, image_base, image_size, vm_entry_rva);
if (!vmctx.init()) {
std::printf(
"[!] failed to init vmctx... this can be for many reasons..."
" try validating your vm entry rva... make sure the binary is "
"unpacked and is"
"protected with VMProtect 2...\n");
return -1;
}
std::printf( "> image base = %p, image size = %p, module base = %p\n", image_base, image_size, module_base );
vm::emu_t emu(&vmctx);
if ( !image_base || !image_size || !module_base )
{
std::printf( "[!] failed to open binary on disk...\n" );
return -1;
}
if (!emu.init()) {
std::printf("[!] failed to init emulator...\n");
return -1;
}
std::vector< vm::instrs::code_block_t > code_blocks;
vm::ctx_t vmctx( module_base, image_base, image_size, vm_entry_rva );
if (!emu.get_trace(code_blocks)) {
std::printf(
"[!] something failed during tracing, review the console for more "
"information...\n");
return -1;
}
if ( !vmctx.init() )
{
std::printf( "[!] failed to init vmctx... this can be for many reasons..."
" try validating your vm entry rva... make sure the binary is unpacked and is"
"protected with VMProtect 2...\n" );
return -1;
std::printf("> number of blocks = %d\n", code_blocks.size());
for (auto &code_block : code_blocks) {
std::printf("> code block starts at = %p\n", code_block.vip_begin);
std::printf("> number of virtual instructions = %d\n",
code_block.vinstrs.size());
std::printf("> does this code block have a jcc? %s\n",
code_block.jcc.has_jcc ? "yes" : "no");
if (code_block.jcc.has_jcc) {
switch (code_block.jcc.type) {
case vm::instrs::jcc_type::branching: {
std::printf("> branch 1 = %p, branch 2 = %p\n",
code_block.jcc.block_addr[0],
code_block.jcc.block_addr[1]);
break;
}
case vm::instrs::jcc_type::absolute: {
std::printf("> branch 1 = %p\n", code_block.jcc.block_addr[0]);
break;
}
case vm::instrs::jcc_type::switch_case: {
std::printf("> switch case blocks:\n");
for (auto idx = 0u; idx < code_block.jcc.block_addr.size(); ++idx)
std::printf(" case block at = 0x%p\n",
code_block.jcc.block_addr[idx]);
break;
}
}
}
}
vm::emu_t emu( &vmctx );
std::printf("> serializing results....\n");
vmp2::v4::file_header file_header;
file_header.magic = VMP_MAGIC;
file_header.epoch_time = std::time(nullptr);
file_header.version = vmp2::version_t::v4;
file_header.module_base = module_base;
file_header.image_base = image_base;
file_header.vm_entry_rva = vm_entry_rva;
file_header.module_offset = sizeof file_header;
file_header.module_size = image_size;
file_header.rtn_count = 1;
file_header.rtn_offset = image_size + sizeof file_header;
vmp2::v4::rtn_t rtn;
std::ofstream output(parser.get<std::string>("out"), std::ios::binary);
output.write(reinterpret_cast<const char *>(&file_header),
sizeof file_header);
output.write(reinterpret_cast<const char *>(module_base), image_size);
std::vector<vmp2::v4::code_block_t *> vmp2_blocks;
for (const auto &code_block : code_blocks) {
const auto _code_block_size =
sizeof(vmp2::v4::code_block_t) +
(code_block.jcc.block_addr.size() * 8) +
code_block.vinstrs.size() * sizeof(vm::instrs::virt_instr_t);
vmp2::v4::code_block_t *_code_block =
reinterpret_cast<vmp2::v4::code_block_t *>(malloc(_code_block_size));
// serialize block meta data...
_code_block->vip_begin = code_block.vip_begin;
_code_block->next_block_offset = _code_block_size;
_code_block->vinstr_count = code_block.vinstrs.size();
_code_block->has_jcc = code_block.jcc.has_jcc;
_code_block->jcc_type = code_block.jcc.type;
_code_block->num_block_addrs = code_block.jcc.block_addr.size();
// serialize jcc branches...
for (auto idx = 0u; idx < code_block.jcc.block_addr.size(); ++idx)
_code_block->branch_addr[idx] = code_block.jcc.block_addr[idx];
auto block_vinstrs = reinterpret_cast<vm::instrs::virt_instr_t *>(
reinterpret_cast<std::uintptr_t>(_code_block) +
sizeof(vmp2::v4::code_block_t) +
(code_block.jcc.block_addr.size() * 8));
for (auto idx = 0u; idx < code_block.vinstrs.size(); ++idx)
block_vinstrs[idx] = code_block.vinstrs[idx];
vmp2_blocks.push_back(_code_block);
}
if ( !emu.init() )
{
std::printf( "[!] failed to init emulator...\n" );
return -1;
}
std::size_t code_blocks_size = sizeof(vmp2::v4::rtn_t::size) +
sizeof(vmp2::v4::rtn_t::code_block_count) +
sizeof(vmp2::v4::rtn_t::vm_enter_offset);
std::for_each(vmp2_blocks.begin(), vmp2_blocks.end(),
[&](vmp2::v4::code_block_t *vmp2_block) -> void {
code_blocks_size += vmp2_block->next_block_offset;
});
rtn.size = code_blocks_size;
rtn.code_block_count = vmp2_blocks.size();
rtn.vm_enter_offset = vm_entry_rva;
output.write(reinterpret_cast<const char *>(&rtn),
sizeof(vmp2::v4::rtn_t::size) +
sizeof(vmp2::v4::rtn_t::code_block_count) +
sizeof(vmp2::v4::rtn_t::vm_enter_offset));
std::for_each(vmp2_blocks.begin(), vmp2_blocks.end(),
[&](vmp2::v4::code_block_t *vmp2_block) -> void {
output.write(reinterpret_cast<const char *>(vmp2_block),
vmp2_block->next_block_offset);
free(vmp2_block);
});
output.close();
} else if (parser.exists("unpack")) {
engine::unpack_t unpacker(module_data);
if (!unpacker.init()) {
std::printf("> failed to init unpacker...\n");
return -1;
}
if ( !emu.get_trace( code_blocks ) )
{
std::printf( "[!] something failed during tracing, review the console for more information...\n" );
return -1;
}
if (!unpacker.unpack(unpacked_bin)) {
std::printf("> failed to unpack binary... refer to log above...\n");
return -1;
}
std::printf( "> number of blocks = %d\n", code_blocks.size() );
for ( auto &code_block : code_blocks )
{
std::printf( "> code block starts at = %p\n", code_block.vip_begin );
std::printf( "> number of virtual instructions = %d\n", code_block.vinstrs.size() );
std::printf( "> does this code block have a jcc? %s\n", code_block.jcc.has_jcc ? "yes" : "no" );
if ( code_block.jcc.has_jcc )
{
switch ( code_block.jcc.type )
{
case vm::instrs::jcc_type::branching:
{
std::printf( "> branch 1 = %p, branch 2 = %p\n", code_block.jcc.block_addr[ 0 ],
code_block.jcc.block_addr[ 1 ] );
break;
}
case vm::instrs::jcc_type::absolute:
{
std::printf( "> branch 1 = %p\n", code_block.jcc.block_addr[ 0 ] );
break;
}
case vm::instrs::jcc_type::switch_case:
{
std::printf( "> switch case blocks:\n" );
for ( auto idx = 0u; idx < code_block.jcc.block_addr.size(); ++idx )
std::printf( " case block at = 0x%p\n", code_block.jcc.block_addr[ idx ] );
break;
}
}
}
}
std::printf("> writing result to = %s\n",
parser.get<std::string>("out").c_str());
std::printf( "> serializing results....\n" );
vmp2::v4::file_header file_header;
file_header.magic = VMP_MAGIC;
file_header.epoch_time = std::time( nullptr );
file_header.version = vmp2::version_t::v4;
file_header.module_base = module_base;
file_header.image_base = image_base;
file_header.vm_entry_rva = vm_entry_rva;
file_header.module_offset = sizeof file_header;
file_header.module_size = image_size;
file_header.rtn_count = 1;
file_header.rtn_offset = image_size + sizeof file_header;
vmp2::v4::rtn_t rtn;
std::ofstream output( parser.get< std::string >( "out" ), std::ios::binary );
output.write( reinterpret_cast< const char * >( &file_header ), sizeof file_header );
output.write( reinterpret_cast< const char * >( module_base ), image_size );
std::vector< vmp2::v4::code_block_t * > vmp2_blocks;
for ( const auto &code_block : code_blocks )
{
const auto _code_block_size = sizeof vmp2::v4::code_block_t + ( code_block.jcc.block_addr.size() * 8 ) +
code_block.vinstrs.size() * sizeof vm::instrs::virt_instr_t;
vmp2::v4::code_block_t *_code_block =
reinterpret_cast< vmp2::v4::code_block_t * >( malloc( _code_block_size ) );
// serialize block meta data...
_code_block->vip_begin = code_block.vip_begin;
_code_block->next_block_offset = _code_block_size;
_code_block->vinstr_count = code_block.vinstrs.size();
_code_block->has_jcc = code_block.jcc.has_jcc;
_code_block->jcc_type = code_block.jcc.type;
_code_block->num_block_addrs = code_block.jcc.block_addr.size();
// serialize jcc branches...
for ( auto idx = 0u; idx < code_block.jcc.block_addr.size(); ++idx )
_code_block->branch_addr[ idx ] = code_block.jcc.block_addr[ idx ];
auto block_vinstrs = reinterpret_cast< vm::instrs::virt_instr_t * >(
reinterpret_cast< std::uintptr_t >( _code_block ) + sizeof vmp2::v4::code_block_t +
( code_block.jcc.block_addr.size() * 8 ) );
for ( auto idx = 0u; idx < code_block.vinstrs.size(); ++idx )
block_vinstrs[ idx ] = code_block.vinstrs[ idx ];
vmp2_blocks.push_back( _code_block );
}
std::ofstream output(parser.get<std::string>("out"), std::ios::binary);
output.write(reinterpret_cast<char *>(unpacked_bin.data()),
unpacked_bin.size());
std::size_t code_blocks_size = sizeof( vmp2::v4::rtn_t::size ) + sizeof( vmp2::v4::rtn_t::code_block_count ) +
sizeof( vmp2::v4::rtn_t::vm_enter_offset );
output.close();
} else if (parser.exists("emuall")) {
auto entries = vm::locate::get_vm_entries(module_base, image_size);
std::for_each( vmp2_blocks.begin(), vmp2_blocks.end(), [ & ]( vmp2::v4::code_block_t *vmp2_block ) -> void {
code_blocks_size += vmp2_block->next_block_offset;
} );
std::vector<
std::pair<std::uintptr_t, std::vector<vm::instrs::code_block_t> > >
virt_rtns;
rtn.size = code_blocks_size;
rtn.code_block_count = vmp2_blocks.size();
rtn.vm_enter_offset = vm_entry_rva;
for (const auto &[vm_enter_offset, encrypted_rva, hndlr_tble] : entries) {
std::printf("> emulating vm enter at rva = 0x%x\n", vm_enter_offset);
vm::ctx_t vm_ctx(module_base, image_base, image_size, vm_enter_offset);
output.write( reinterpret_cast< const char * >( &rtn ), sizeof( vmp2::v4::rtn_t::size ) +
sizeof( vmp2::v4::rtn_t::code_block_count ) +
sizeof( vmp2::v4::rtn_t::vm_enter_offset ) );
if (!vm_ctx.init()) {
std::printf(
"[!] failed to init vmctx... this can be for many reasons..."
" try validating your vm entry rva... make sure the binary is "
"unpacked and is"
"protected with VMProtect 2...\n");
return -1;
}
std::for_each( vmp2_blocks.begin(), vmp2_blocks.end(), [ & ]( vmp2::v4::code_block_t *vmp2_block ) -> void {
output.write( reinterpret_cast< const char * >( vmp2_block ), vmp2_block->next_block_offset );
free( vmp2_block );
} );
output.close();
}
else if ( parser.exists( "unpack" ) && parser.exists( "out" ) )
{
std::vector< std::uint8_t > packed_bin, unpacked_bin;
if ( !umtils->open_binary_file( parser.get< std::string >( "unpack" ), packed_bin ) )
{
std::printf( "> failed to read bin off disk...\n" );
return -1;
}
vm::emu_t emu(&vm_ctx);
engine::unpack_t unpacker( packed_bin );
if (!emu.init()) {
std::printf("[!] failed to init emulator...\n");
return -1;
}
if ( !unpacker.init() )
{
std::printf( "> failed to init unpacker...\n" );
return -1;
}
std::vector<vm::instrs::code_block_t> code_blocks;
if ( !unpacker.unpack( unpacked_bin ) )
{
std::printf( "> failed to unpack binary... refer to log above...\n" );
return -1;
}
if (!emu.get_trace(code_blocks)) {
std::printf(
"[!] something failed during tracing, review the console for more "
"information...\n");
continue;
}
std::printf( "> writing result to = %s\n", parser.get< std::string >( "out" ).c_str() );
std::ofstream output( parser.get< std::string >( "out" ), std::ios::binary );
output.write( reinterpret_cast< char * >( unpacked_bin.data() ), unpacked_bin.size() );
output.close();
std::printf("> number of blocks = %d\n", code_blocks.size());
virt_rtns.push_back({vm_enter_offset, code_blocks});
}
else if ( parser.exists( "bin" ) && parser.exists( "emuall" ) && parser.exists( "out" ) )
{
const auto module_base = reinterpret_cast< std::uintptr_t >(
LoadLibraryExA( parser.get< std::string >( "bin" ).c_str(), NULL, DONT_RESOLVE_DLL_REFERENCES ) );
const auto image_base = umtils->image_base( parser.get< std::string >( "bin" ).c_str() );
const auto image_size = NT_HEADER( module_base )->OptionalHeader.SizeOfImage;
auto vm_handler_tables = vm::locate::all_handler_tables( module_base );
auto vm_enters = vm::locate::all_vm_enters( module_base, vm_handler_tables );
std::vector< std::pair< std::uintptr_t, std::vector< vm::instrs::code_block_t > > > virt_rtns;
for ( const auto &[ vm_enter_offset, encrypted_rva ] : vm_enters )
{
std::printf( "> emulating vm enter at rva = 0x%x\n", vm_enter_offset );
vm::ctx_t vm_ctx( module_base, image_base, image_size, vm_enter_offset );
if ( !vm_ctx.init() )
{
std::printf( "[!] failed to init vmctx... this can be for many reasons..."
" try validating your vm entry rva... make sure the binary is unpacked and is"
"protected with VMProtect 2...\n" );
return -1;
}
vm::emu_t emu( &vm_ctx );
if ( !emu.init() )
{
std::printf( "[!] failed to init emulator...\n" );
return -1;
}
std::vector< vm::instrs::code_block_t > code_blocks;
if ( !emu.get_trace( code_blocks ) )
{
std::printf( "[!] something failed during tracing, review the console for more information...\n" );
continue;
}
std::printf( "> number of blocks = %d\n", code_blocks.size() );
virt_rtns.push_back( { vm_enter_offset, code_blocks } );
}
std::printf( "> traced %d virtual routines...\n", virt_rtns.size() );
std::printf( "> serializing results....\n" );
vmp2::v4::file_header file_header;
file_header.magic = VMP_MAGIC;
file_header.epoch_time = std::time( nullptr );
file_header.version = vmp2::version_t::v4;
file_header.module_base = module_base;
file_header.image_base = image_base;
file_header.vm_entry_rva = 0ull;
file_header.module_offset = sizeof file_header;
file_header.module_size = image_size;
file_header.rtn_count = virt_rtns.size();
file_header.rtn_offset = image_size + sizeof file_header;
std::ofstream output( parser.get< std::string >( "out" ), std::ios::binary );
output.write( reinterpret_cast< const char * >( &file_header ), sizeof file_header );
output.write( reinterpret_cast< const char * >( module_base ), image_size );
for ( auto &[ vm_enter_offset, virt_rtn ] : virt_rtns )
{
vmp2::v4::rtn_t rtn{ virt_rtn.size() };
std::vector< vmp2::v4::code_block_t * > vmp2_blocks;
for ( const auto &code_block : virt_rtn )
{
const auto _code_block_size = sizeof vmp2::v4::code_block_t + ( code_block.jcc.block_addr.size() * 8 ) +
code_block.vinstrs.size() * sizeof vm::instrs::virt_instr_t;
vmp2::v4::code_block_t *_code_block =
reinterpret_cast< vmp2::v4::code_block_t * >( malloc( _code_block_size ) );
// serialize block meta data...
_code_block->vip_begin = code_block.vip_begin;
_code_block->next_block_offset = _code_block_size;
_code_block->vinstr_count = code_block.vinstrs.size();
_code_block->has_jcc = code_block.jcc.has_jcc;
_code_block->jcc_type = code_block.jcc.type;
_code_block->num_block_addrs = code_block.jcc.block_addr.size();
// serialize jcc branches...
for ( auto idx = 0u; idx < code_block.jcc.block_addr.size(); ++idx )
_code_block->branch_addr[ idx ] = code_block.jcc.block_addr[ idx ];
auto block_vinstrs = reinterpret_cast< vm::instrs::virt_instr_t * >(
reinterpret_cast< std::uintptr_t >( _code_block ) + sizeof vmp2::v4::code_block_t +
( code_block.jcc.block_addr.size() * 8 ) );
for ( auto idx = 0u; idx < code_block.vinstrs.size(); ++idx )
block_vinstrs[ idx ] = code_block.vinstrs[ idx ];
vmp2_blocks.push_back( _code_block );
}
std::size_t code_blocks_size = sizeof( vmp2::v4::rtn_t::size ) +
sizeof( vmp2::v4::rtn_t::vm_enter_offset ) +
sizeof( vmp2::v4::rtn_t::code_block_count );
std::for_each( vmp2_blocks.begin(), vmp2_blocks.end(), [ & ]( vmp2::v4::code_block_t *vmp2_block ) -> void {
code_blocks_size += vmp2_block->next_block_offset;
} );
rtn.size = code_blocks_size;
rtn.code_block_count = vmp2_blocks.size();
rtn.vm_enter_offset = vm_enter_offset;
output.write( reinterpret_cast< const char * >( &rtn ), sizeof( vmp2::v4::rtn_t::size ) +
sizeof( vmp2::v4::rtn_t::code_block_count ) +
sizeof( vmp2::v4::rtn_t::vm_enter_offset ) );
std::for_each( vmp2_blocks.begin(), vmp2_blocks.end(), [ & ]( vmp2::v4::code_block_t *vmp2_block ) -> void {
output.write( reinterpret_cast< const char * >( vmp2_block ), vmp2_block->next_block_offset );
free( vmp2_block );
} );
}
output.close();
}
else if ( parser.exists( "bin" ) && parser.exists( "locateconst" ) )
{
const auto module_base = reinterpret_cast< std::uintptr_t >(
LoadLibraryExA( parser.get< std::string >( "bin" ).c_str(), NULL, DONT_RESOLVE_DLL_REFERENCES ) );
const auto const_val = std::strtoull( parser.get< std::string >( "locateconst" ).c_str(), nullptr, 16 );
const auto image_base = umtils->image_base( parser.get< std::string >( "bin" ).c_str() );
const auto image_size = NT_HEADER( module_base )->OptionalHeader.SizeOfImage;
auto vm_handler_tables = vm::locate::all_handler_tables( module_base );
auto vm_enters = vm::locate::all_vm_enters( module_base, vm_handler_tables );
std::printf( "> number of vm enters = %d\n", vm_enters.size() );
for ( const auto &[ vm_enter_offset, encrypted_rva ] : vm_enters )
{
std::printf( "> emulating vm enter at rva = 0x%x\n", vm_enter_offset );
vm::ctx_t vm_ctx( module_base, image_base, image_size, vm_enter_offset );
if ( !vm_ctx.init() )
{
std::printf( "[!] failed to init vmctx... this can be for many reasons..."
" try validating your vm entry rva... make sure the binary is unpacked and is"
"protected with VMProtect 2...\n" );
return -1;
}
vm::emu_t emu( &vm_ctx );
if ( !emu.init() )
{
std::printf( "[!] failed to init emulator...\n" );
return -1;
}
std::vector< vm::instrs::code_block_t > code_blocks;
if ( !emu.get_trace( code_blocks ) )
{
std::printf( "[!] something failed during tracing, review the console for more information...\n" );
return -1;
}
std::printf( "> number of blocks = %d\n", code_blocks.size() );
for ( auto &code_block : code_blocks )
{
for ( const auto &vinstr : code_block.vinstrs )
{
if ( vinstr.operand.has_imm && vinstr.operand.imm.u == const_val )
{
std::printf( "> found constant in vm enter at = 0x%x\n", vm_enter_offset );
std::getchar();
}
}
}
}
std::printf("> traced %d virtual routines...\n", virt_rtns.size());
std::printf("> serializing results....\n");
vmp2::v4::file_header file_header;
file_header.magic = VMP_MAGIC;
file_header.epoch_time = std::time(nullptr);
file_header.version = vmp2::version_t::v4;
file_header.module_base = module_base;
file_header.image_base = image_base;
file_header.vm_entry_rva = 0ull;
file_header.module_offset = sizeof file_header;
file_header.module_size = image_size;
file_header.rtn_count = virt_rtns.size();
file_header.rtn_offset = image_size + sizeof file_header;
std::ofstream output(parser.get<std::string>("out"), std::ios::binary);
output.write(reinterpret_cast<const char *>(&file_header),
sizeof file_header);
output.write(reinterpret_cast<const char *>(module_base), image_size);
for (auto &[vm_enter_offset, virt_rtn] : virt_rtns) {
vmp2::v4::rtn_t rtn{(u32)virt_rtn.size()};
std::vector<vmp2::v4::code_block_t *> vmp2_blocks;
for (const auto &code_block : virt_rtn) {
const auto _code_block_size =
sizeof(vmp2::v4::code_block_t) +
(code_block.jcc.block_addr.size() * 8) +
code_block.vinstrs.size() * sizeof(vm::instrs::virt_instr_t);
vmp2::v4::code_block_t *_code_block =
reinterpret_cast<vmp2::v4::code_block_t *>(
malloc(_code_block_size));
// serialize block meta data...
_code_block->vip_begin = code_block.vip_begin;
_code_block->next_block_offset = _code_block_size;
_code_block->vinstr_count = code_block.vinstrs.size();
_code_block->has_jcc = code_block.jcc.has_jcc;
_code_block->jcc_type = code_block.jcc.type;
_code_block->num_block_addrs = code_block.jcc.block_addr.size();
// serialize jcc branches...
for (auto idx = 0u; idx < code_block.jcc.block_addr.size(); ++idx)
_code_block->branch_addr[idx] = code_block.jcc.block_addr[idx];
auto block_vinstrs = reinterpret_cast<vm::instrs::virt_instr_t *>(
reinterpret_cast<std::uintptr_t>(_code_block) +
sizeof(vmp2::v4::code_block_t) +
(code_block.jcc.block_addr.size() * 8));
for (auto idx = 0u; idx < code_block.vinstrs.size(); ++idx)
block_vinstrs[idx] = code_block.vinstrs[idx];
vmp2_blocks.push_back(_code_block);
}
std::size_t code_blocks_size = sizeof(vmp2::v4::rtn_t::size) +
sizeof(vmp2::v4::rtn_t::vm_enter_offset) +
sizeof(vmp2::v4::rtn_t::code_block_count);
std::for_each(vmp2_blocks.begin(), vmp2_blocks.end(),
[&](vmp2::v4::code_block_t *vmp2_block) -> void {
code_blocks_size += vmp2_block->next_block_offset;
});
rtn.size = code_blocks_size;
rtn.code_block_count = vmp2_blocks.size();
rtn.vm_enter_offset = vm_enter_offset;
output.write(reinterpret_cast<const char *>(&rtn),
sizeof(vmp2::v4::rtn_t::size) +
sizeof(vmp2::v4::rtn_t::code_block_count) +
sizeof(vmp2::v4::rtn_t::vm_enter_offset));
std::for_each(vmp2_blocks.begin(), vmp2_blocks.end(),
[&](vmp2::v4::code_block_t *vmp2_block) -> void {
output.write(reinterpret_cast<const char *>(vmp2_block),
vmp2_block->next_block_offset);
free(vmp2_block);
});
}
output.close();
}
}

942
src/unpacker.cpp
Unescape View File

@ -1,507 +1,497 @@
#include <unpacker.hpp>
namespace engine
{
unpack_t::unpack_t( const std::vector< std::uint8_t > &packed_bin )
: bin( packed_bin ), uc_ctx( nullptr ), heap_offset( 0ull ), pack_section_offset( 0ull )
{
win_img = reinterpret_cast< win::image_t<> * >( bin.data() );
img_base = win_img->get_nt_headers()->optional_header.image_base;
img_size = win_img->get_nt_headers()->optional_header.size_image;
std::printf( "> image base = 0x%p, image size = 0x%x\n", img_base, img_size );
namespace engine {
unpack_t::unpack_t(const std::vector<std::uint8_t> &packed_bin)
: bin(packed_bin),
uc_ctx(nullptr),
heap_offset(0ull),
pack_section_offset(0ull) {
win_img = reinterpret_cast<win::image_t<> *>(bin.data());
img_base = win_img->get_nt_headers()->optional_header.image_base;
img_size = win_img->get_nt_headers()->optional_header.size_image;
std::printf("> image base = 0x%p, image size = 0x%x\n", img_base, img_size);
}
unpack_t::~unpack_t(void) {
if (uc_ctx) uc_close(uc_ctx);
for (auto &ptr : uc_hooks)
if (ptr) delete ptr;
}
bool unpack_t::init(void) {
uc_err err;
if ((err = uc_open(UC_ARCH_X86, UC_MODE_64, &uc_ctx))) {
std::printf("> uc_open err = %d\n", err);
return false;
}
if ((err = uc_mem_map(uc_ctx, IAT_VECTOR_TABLE, PAGE_4KB, UC_PROT_ALL))) {
std::printf("> uc_mem_map iat vector table err = %d\n", err);
return false;
}
if ((err = uc_mem_map(uc_ctx, STACK_BASE, STACK_SIZE, UC_PROT_ALL))) {
std::printf("> uc_mem_map stack err, reason = %d\n", err);
return false;
}
if ((err = uc_mem_map(uc_ctx, img_base, img_size, UC_PROT_ALL))) {
std::printf("> map memory failed, reason = %d\n", err);
return false;
}
// init iat vector table full of 'ret' instructions...
auto c3_page = malloc(PAGE_4KB);
{
memset(c3_page, 0xC3, PAGE_4KB);
if ((err = uc_mem_write(uc_ctx, IAT_VECTOR_TABLE, c3_page, PAGE_4KB))) {
std::printf("> failed to init iat vector table...\n");
free(c3_page);
return false;
}
unpack_t::~unpack_t( void )
{
if ( uc_ctx )
uc_close( uc_ctx );
for ( auto &ptr : uc_hooks )
if ( ptr )
delete ptr;
}
bool unpack_t::init( void )
{
uc_err err;
if ( ( err = uc_open( UC_ARCH_X86, UC_MODE_64, &uc_ctx ) ) )
{
std::printf( "> uc_open err = %d\n", err );
return false;
}
if ( ( err = uc_mem_map( uc_ctx, IAT_VECTOR_TABLE, PAGE_4KB, UC_PROT_ALL ) ) )
{
std::printf( "> uc_mem_map iat vector table err = %d\n", err );
return false;
}
if ( ( err = uc_mem_map( uc_ctx, STACK_BASE, STACK_SIZE, UC_PROT_ALL ) ) )
{
std::printf( "> uc_mem_map stack err, reason = %d\n", err );
return false;
}
if ( ( err = uc_mem_map( uc_ctx, img_base, img_size, UC_PROT_ALL ) ) )
{
std::printf( "> map memory failed, reason = %d\n", err );
return false;
}
// init iat vector table full of 'ret' instructions...
auto c3_page = malloc( PAGE_4KB );
{
memset( c3_page, 0xC3, PAGE_4KB );
if ( ( err = uc_mem_write( uc_ctx, IAT_VECTOR_TABLE, c3_page, PAGE_4KB ) ) )
{
std::printf( "> failed to init iat vector table...\n" );
free( c3_page );
return false;
}
}
free( c3_page );
map_bin.resize( img_size );
memcpy( map_bin.data(), bin.data(), // copies pe headers (includes section headers)
win_img->get_nt_headers()->optional_header.size_headers );
win::section_header_t *sec_begin = win_img->get_nt_headers()->get_sections(),
*sec_end = sec_begin + win_img->get_nt_headers()->file_header.num_sections;
std::for_each( sec_begin, sec_end, [ & ]( const win::section_header_t &sec_header ) {
memcpy( map_bin.data() + sec_header.virtual_address, bin.data() + sec_header.ptr_raw_data,
sec_header.size_raw_data );
} );
auto basereloc_dir = win_img->get_directory( win::directory_id::directory_entry_basereloc );
auto reloc_dir = reinterpret_cast< win::reloc_directory_t * >( basereloc_dir->rva + map_bin.data() );
win::reloc_block_t *reloc_block = &reloc_dir->first_block;
// apply relocations to all sections...
while ( reloc_block->base_rva && reloc_block->size_block )
{
std::for_each( reloc_block->begin(), reloc_block->end(), [ & ]( win::reloc_entry_t &entry ) {
switch ( entry.type )
{
case win::reloc_type_id::rel_based_dir64:
{
auto reloc_at =
reinterpret_cast< std::uintptr_t * >( entry.offset + reloc_block->base_rva + map_bin.data() );
*reloc_at = img_base + ( ( *reloc_at ) - img_base );
break;
}
default:
break;
}
} );
reloc_block = reloc_block->next();
}
// iat hook specific function...
for ( auto import_dir = reinterpret_cast< win::import_directory_t * >(
win_img->get_directory( win::directory_id::directory_entry_import )->rva + map_bin.data() );
import_dir->rva_name; ++import_dir )
{
for ( auto iat_thunk =
reinterpret_cast< win::image_thunk_data_t<> * >( import_dir->rva_first_thunk + map_bin.data() );
iat_thunk->address; ++iat_thunk )
{
if ( iat_thunk->is_ordinal )
continue;
auto iat_name = reinterpret_cast< win::image_named_import_t * >( iat_thunk->address + map_bin.data() );
if ( iat_hooks.find( iat_name->name ) != iat_hooks.end() )
iat_thunk->function = iat_hooks[ iat_name->name ].first + IAT_VECTOR_TABLE;
}
}
// map the entire map buffer into unicorn-engine since we have set everything else up...
if ( ( err = uc_mem_write( uc_ctx, img_base, map_bin.data(), map_bin.size() ) ) )
{
std::printf( "> failed to write memory... reason = %d\n", err );
return false;
}
// setup unicorn-engine hooks on IAT vector table, sections with 0 raw size/ptr, and an invalid memory
// handler...
uc_hooks.push_back( new uc_hook );
if ( ( err = uc_hook_add( uc_ctx, uc_hooks.back(), UC_HOOK_CODE, &engine::unpack_t::iat_dispatcher, this,
IAT_VECTOR_TABLE, IAT_VECTOR_TABLE + PAGE_4KB ) ) )
{
std::printf( "> uc_hook_add error, reason = %d\n", err );
return false;
}
uc_hooks.push_back( new uc_hook );
if ( ( err = uc_hook_add( uc_ctx, uc_hooks.back(),
UC_HOOK_MEM_READ_UNMAPPED | UC_HOOK_MEM_WRITE_UNMAPPED | UC_HOOK_MEM_FETCH_UNMAPPED |
UC_HOOK_INSN_INVALID,
&engine::unpack_t::invalid_mem, this, true, false ) ) )
{
std::printf( "> uc_hook_add error, reason = %d\n", err );
return false;
}
// execution break points on all sections that are executable but have no physical size on disk...
std::for_each( sec_begin, sec_end, [ & ]( win::section_header_t &header ) {
if ( !header.ptr_raw_data && !header.size_raw_data && header.characteristics.mem_execute &&
header.characteristics.mem_write && !header.is_discardable() )
{
uc_hooks.push_back( new uc_hook );
if ( ( err = uc_hook_add( uc_ctx, uc_hooks.back(), UC_HOOK_CODE | UC_HOOK_MEM_WRITE,
&engine::unpack_t::unpack_section_callback, this,
header.virtual_address + img_base,
header.virtual_address + header.virtual_size + img_base ) ) )
{
std::printf( "> failed to add hook... reason = %d\n", err );
return false;
}
pack_section_offset = header.virtual_address + header.virtual_size;
}
else if ( header.characteristics.mem_execute )
{
uc_hooks.push_back( new uc_hook );
if ( ( err = uc_hook_add( uc_ctx, uc_hooks.back(), UC_HOOK_CODE, &engine::unpack_t::code_exec_callback,
this, header.virtual_address + img_base,
header.virtual_address + header.virtual_size + img_base ) ) )
{
std::printf( "> failed to add hook... reason = %d\n", err );
return false;
}
}
free(c3_page);
map_bin.resize(img_size);
memcpy(map_bin.data(),
bin.data(), // copies pe headers (includes section headers)
win_img->get_nt_headers()->optional_header.size_headers);
win::section_header_t *sec_begin = win_img->get_nt_headers()->get_sections(),
*sec_end =
sec_begin +
win_img->get_nt_headers()->file_header.num_sections;
std::for_each(
sec_begin, sec_end, [&](const win::section_header_t &sec_header) {
memcpy(map_bin.data() + sec_header.virtual_address,
bin.data() + sec_header.ptr_raw_data, sec_header.size_raw_data);
});
auto basereloc_dir =
win_img->get_directory(win::directory_id::directory_entry_basereloc);
auto reloc_dir = reinterpret_cast<win::reloc_directory_t *>(
basereloc_dir->rva + map_bin.data());
win::reloc_block_t *reloc_block = &reloc_dir->first_block;
// apply relocations to all sections...
while (reloc_block->base_rva && reloc_block->size_block) {
std::for_each(
reloc_block->begin(), reloc_block->end(),
[&](win::reloc_entry_t &entry) {
switch (entry.type) {
case win::reloc_type_id::rel_based_dir64: {
auto reloc_at = reinterpret_cast<std::uintptr_t *>(
entry.offset + reloc_block->base_rva + map_bin.data());
*reloc_at = img_base + ((*reloc_at) - img_base);
break;
}
} );
return true;
default:
break;
}
});
reloc_block = reloc_block->next();
}
// iat hook specific function...
for (auto import_dir = reinterpret_cast<win::import_directory_t *>(
win_img->get_directory(win::directory_id::directory_entry_import)
->rva +
map_bin.data());
import_dir->rva_name; ++import_dir) {
for (auto iat_thunk = reinterpret_cast<win::image_thunk_data_t<> *>(
import_dir->rva_first_thunk + map_bin.data());
iat_thunk->address; ++iat_thunk) {
if (iat_thunk->is_ordinal) continue;
auto iat_name = reinterpret_cast<win::image_named_import_t *>(
iat_thunk->address + map_bin.data());
if (iat_hooks.find(iat_name->name) != iat_hooks.end())
iat_thunk->function =
iat_hooks[iat_name->name].first + IAT_VECTOR_TABLE;
}
bool unpack_t::unpack( std::vector< std::uint8_t > &output )
{
uc_err err;
auto nt_headers = win_img->get_nt_headers();
std::uintptr_t rip = nt_headers->optional_header.entry_point + img_base, rsp = STACK_BASE + STACK_SIZE;
if ( ( err = uc_reg_write( uc_ctx, UC_X86_REG_RSP, &rsp ) ) )
{
std::printf( "> uc_reg_write error, reason = %d\n", err );
return false;
}
if ( ( err = uc_reg_write( uc_ctx, UC_X86_REG_RIP, &rip ) ) )
{
std::printf( "> uc_reg_write error, reason = %d\n", err );
return false;
}
std::printf( "> beginning execution at = 0x%p\n", rip );
if ( ( err = uc_emu_start( uc_ctx, rip, 0ull, 0ull, 0ull ) ) )
{
std::printf( "> error starting emu... reason = %d\n", err );
return false;
}
output.resize( img_size );
if ( ( err = uc_mem_read( uc_ctx, img_base, output.data(), output.size() ) ) )
{
std::printf( "> uc_mem_read failed... err = %d\n", err );
return false;
}
auto output_img = reinterpret_cast< win::image_t<> * >( output.data() );
auto sections = output_img->get_nt_headers()->get_sections();
auto section_cnt = output_img->get_file_header()->num_sections;
// { section virtual address -> vector of section offset to reloc }
std::map< std::uint32_t, std::vector< std::uint16_t > > new_relocs;
// search executable sections for MOV RAX, 00 00 00 00 00 00 00 00...
std::for_each( sections, sections + section_cnt, [ & ]( win::section_header_t &header ) {
if ( header.characteristics.mem_execute )
{
auto result = output.data() + header.virtual_address;
do
{
result = reinterpret_cast< std::uint8_t * >( xtils::um_t::get_instance()->sigscan(
result,
header.virtual_size -
( reinterpret_cast< std::uintptr_t >( result ) -
( header.virtual_address + reinterpret_cast< std::uintptr_t >( output.data() ) ) ),
MOV_RAX_0_SIG, MOV_RAX_0_MASK ) );
if ( result )
{
result += 2; // advance ahead of the 0x48 0xB8...
// offset from section begin...
auto reloc_offset =
( reinterpret_cast< std::uintptr_t >( result ) ) -
reinterpret_cast< std::uintptr_t >( output.data() + header.virtual_address );
new_relocs[ ( header.virtual_address + reloc_offset ) & ~0xFFFull ].push_back( reloc_offset );
}
} while ( result );
}
header.ptr_raw_data = header.virtual_address;
header.size_raw_data = header.virtual_size;
} );
// determines if a relocation block exists for a given page...
static const auto has_reloc_page = [ & ]( std::uint32_t page ) -> bool {
auto img = reinterpret_cast< win::image_t<> * >( output.data() );
auto sections = img->get_nt_headers()->get_sections();
auto section_cnt = img->get_file_header()->num_sections;
auto basereloc_dir = img->get_directory( win::directory_id::directory_entry_basereloc );
auto reloc_dir = reinterpret_cast< win::reloc_directory_t * >( basereloc_dir->rva + output.data() );
win::reloc_block_t *reloc_block = &reloc_dir->first_block;
while ( reloc_block->base_rva && reloc_block->size_block )
{
if ( reloc_block->base_rva == page )
return true;
reloc_block = reloc_block->next();
}
// map the entire map buffer into unicorn-engine since we have set everything
// else up...
if ((err = uc_mem_write(uc_ctx, img_base, map_bin.data(), map_bin.size()))) {
std::printf("> failed to write memory... reason = %d\n", err);
return false;
}
// setup unicorn-engine hooks on IAT vector table, sections with 0 raw
// size/ptr, and an invalid memory handler...
uc_hooks.push_back(new uc_hook);
if ((err = uc_hook_add(uc_ctx, uc_hooks.back(), UC_HOOK_CODE,
(void *)&engine::unpack_t::iat_dispatcher, this,
IAT_VECTOR_TABLE, IAT_VECTOR_TABLE + PAGE_4KB))) {
std::printf("> uc_hook_add error, reason = %d\n", err);
return false;
}
uc_hooks.push_back(new uc_hook);
if ((err = uc_hook_add(
uc_ctx, uc_hooks.back(),
UC_HOOK_MEM_READ_UNMAPPED | UC_HOOK_MEM_WRITE_UNMAPPED |
UC_HOOK_MEM_FETCH_UNMAPPED | UC_HOOK_INSN_INVALID,
(void *)&engine::unpack_t::invalid_mem, this, true, false))) {
std::printf("> uc_hook_add error, reason = %d\n", err);
return false;
}
// execution break points on all sections that are executable but have no
// physical size on disk...
std::for_each(sec_begin, sec_end, [&](win::section_header_t &header) {
if (!header.ptr_raw_data && !header.size_raw_data &&
header.characteristics.mem_execute &&
header.characteristics.mem_write && !header.is_discardable()) {
uc_hooks.push_back(new uc_hook);
if ((err = uc_hook_add(
uc_ctx, uc_hooks.back(), UC_HOOK_CODE | UC_HOOK_MEM_WRITE,
(void *)&engine::unpack_t::unpack_section_callback, this,
header.virtual_address + img_base,
header.virtual_address + header.virtual_size + img_base))) {
std::printf("> failed to add hook... reason = %d\n", err);
return false;
}
pack_section_offset = header.virtual_address + header.virtual_size;
} else if (header.characteristics.mem_execute) {
uc_hooks.push_back(new uc_hook);
if ((err = uc_hook_add(
uc_ctx, uc_hooks.back(), UC_HOOK_CODE,
(void *)&engine::unpack_t::code_exec_callback, this,
header.virtual_address + img_base,
header.virtual_address + header.virtual_size + img_base))) {
std::printf("> failed to add hook... reason = %d\n", err);
return false;
}
}
});
return true;
}
bool unpack_t::unpack(std::vector<std::uint8_t> &output) {
uc_err err;
auto nt_headers = win_img->get_nt_headers();
std::uintptr_t rip = nt_headers->optional_header.entry_point + img_base,
rsp = STACK_BASE + STACK_SIZE;
if ((err = uc_reg_write(uc_ctx, UC_X86_REG_RSP, &rsp))) {
std::printf("> uc_reg_write error, reason = %d\n", err);
return false;
}
if ((err = uc_reg_write(uc_ctx, UC_X86_REG_RIP, &rip))) {
std::printf("> uc_reg_write error, reason = %d\n", err);
return false;
}
std::printf("> beginning execution at = 0x%p\n", rip);
if ((err = uc_emu_start(uc_ctx, rip, 0ull, 0ull, 0ull))) {
std::printf("> error starting emu... reason = %d\n", err);
return false;
}
output.resize(img_size);
if ((err = uc_mem_read(uc_ctx, img_base, output.data(), output.size()))) {
std::printf("> uc_mem_read failed... err = %d\n", err);
return false;
}
auto output_img = reinterpret_cast<win::image_t<> *>(output.data());
auto sections = output_img->get_nt_headers()->get_sections();
auto section_cnt = output_img->get_file_header()->num_sections;
// { section virtual address -> vector of section offset to reloc }
std::map<std::uint32_t, std::vector<std::uint16_t> > new_relocs;
// search executable sections for MOV RAX, 00 00 00 00 00 00 00 00...
std::for_each(
sections, sections + section_cnt, [&](win::section_header_t &header) {
if (header.characteristics.mem_execute) {
auto result = output.data() + header.virtual_address;
do {
result = reinterpret_cast<std::uint8_t *>(vm::locate::sigscan(
result,
header.virtual_size -
(reinterpret_cast<std::uintptr_t>(result) -
(header.virtual_address +
reinterpret_cast<std::uintptr_t>(output.data()))),
MOV_RAX_0_SIG, MOV_RAX_0_MASK));
if (result) {
result += 2; // advance ahead of the 0x48 0xB8...
// offset from section begin...
auto reloc_offset = (reinterpret_cast<std::uintptr_t>(result)) -
reinterpret_cast<std::uintptr_t>(
output.data() + header.virtual_address);
new_relocs[(header.virtual_address + reloc_offset) & ~0xFFFull]
.push_back(reloc_offset);
}
return false;
};
// calc size to add new reloc info...
std::size_t resize_cnt = 0ull;
for ( const auto &[ reloc_rva, relocs ] : new_relocs )
if ( !has_reloc_page( reloc_rva ) )
resize_cnt += sizeof( win::reloc_block_t ) + ( relocs.size() * sizeof( win::reloc_entry_t ) );
// last block needs to contain 0 for block_rva and size_block...
if ( resize_cnt )
resize_cnt += sizeof win::reloc_block_t;
output.resize( output.size() + resize_cnt );
output_img = reinterpret_cast< win::image_t<> * >( output.data() );
auto basereloc_dir = output_img->get_directory( win::directory_id::directory_entry_basereloc );
auto reloc_dir = reinterpret_cast< win::reloc_directory_t * >( basereloc_dir->rva + output.data() );
basereloc_dir->size += resize_cnt;
for ( const auto &[ reloc_rva, relocs ] : new_relocs )
{
if ( has_reloc_page( reloc_rva ) )
continue;
win::reloc_block_t *reloc_block = &reloc_dir->first_block;
while ( reloc_block->base_rva && reloc_block->size_block )
reloc_block = reloc_block->next();
reloc_block->base_rva = reloc_rva;
reloc_block->size_block = relocs.size() * sizeof( win::reloc_entry_t ) + sizeof uint64_t;
reloc_block->next()->base_rva = 0ull;
reloc_block->next()->size_block = 0ull;
for ( auto idx = 0u; idx < relocs.size(); ++idx )
{
reloc_block->entries[ idx ].type = win::reloc_type_id::rel_based_dir64;
reloc_block->entries[ idx ].offset = relocs[ idx ];
}
} while (result);
}
return true;
}
void unpack_t::local_alloc_hook( uc_engine *uc_ctx, unpack_t *obj )
{
uc_err err;
std::uintptr_t rax, rdx;
header.ptr_raw_data = header.virtual_address;
header.size_raw_data = header.virtual_size;
});
if ( ( err = uc_reg_read( uc_ctx, UC_X86_REG_RDX, &rdx ) ) )
{
std::printf( "> failed to read RDX... reason = %d\n", rdx );
return;
}
// determines if a relocation block exists for a given page...
static const auto has_reloc_page = [&](std::uint32_t page) -> bool {
auto img = reinterpret_cast<win::image_t<> *>(output.data());
auto sections = img->get_nt_headers()->get_sections();
auto section_cnt = img->get_file_header()->num_sections;
auto size = ( ( rdx + PAGE_4KB ) & ~0xFFFull );
if ( ( err = uc_mem_map( uc_ctx, HEAP_BASE + obj->heap_offset, size, UC_PROT_ALL ) ) )
{
std::printf( "> failed to allocate memory... reason = %d\n", err );
return;
}
auto basereloc_dir =
img->get_directory(win::directory_id::directory_entry_basereloc);
auto reloc_dir = reinterpret_cast<win::reloc_directory_t *>(
basereloc_dir->rva + output.data());
win::reloc_block_t *reloc_block = &reloc_dir->first_block;
rax = HEAP_BASE + obj->heap_offset;
obj->heap_offset += size;
while (reloc_block->base_rva && reloc_block->size_block) {
if (reloc_block->base_rva == page) return true;
if ( ( err = uc_reg_write( uc_ctx, UC_X86_REG_RAX, &rax ) ) )
{
std::printf( "> failed to write rax... reason = %d\n", err );
return;
}
reloc_block = reloc_block->next();
}
void unpack_t::local_free_hook( uc_engine *uc_ctx, unpack_t *obj )
{
uc_err err;
std::uintptr_t rax = 0ull;
return false;
};
if ( ( err = uc_reg_write( uc_ctx, UC_X86_REG_RAX, &rax ) ) )
{
std::printf( "> failed to write rax... reason = %d\n", err );
return;
}
}
void unpack_t::load_library_hook( uc_engine *uc_ctx, unpack_t *obj )
{
uc_err err;
std::uintptr_t rcx = 0ull;
// calc size to add new reloc info...
std::size_t resize_cnt = 0ull;
for (const auto &[reloc_rva, relocs] : new_relocs)
if (!has_reloc_page(reloc_rva))
resize_cnt += sizeof(win::reloc_block_t) +
(relocs.size() * sizeof(win::reloc_entry_t));
if ( ( err = uc_reg_read( uc_ctx, UC_X86_REG_RCX, &rcx ) ) )
{
std::printf( "> uc_reg_read error, reason = %d\n", err );
return;
}
// last block needs to contain 0 for block_rva and size_block...
if (resize_cnt) resize_cnt += sizeof(win::reloc_block_t);
char buff[ 256 ];
uc_strcpy( uc_ctx, buff, rcx );
std::printf( "> LoadLibraryA(\"%s\")\n", buff );
output.resize(output.size() + resize_cnt);
output_img = reinterpret_cast<win::image_t<> *>(output.data());
auto module_base = reinterpret_cast< std::uintptr_t >( LoadLibraryA( buff ) );
auto basereloc_dir =
output_img->get_directory(win::directory_id::directory_entry_basereloc);
auto reloc_dir = reinterpret_cast<win::reloc_directory_t *>(
basereloc_dir->rva + output.data());
auto module_size =
reinterpret_cast< win::image_t<> * >( module_base )->get_nt_headers()->optional_header.size_image;
basereloc_dir->size += resize_cnt;
for (const auto &[reloc_rva, relocs] : new_relocs) {
if (has_reloc_page(reloc_rva)) continue;
if ( std::find( obj->loaded_modules.begin(), obj->loaded_modules.end(), module_base ) !=
obj->loaded_modules.end() )
{
if ( ( err = uc_reg_write( uc_ctx, UC_X86_REG_RAX, &module_base ) ) )
{
std::printf( "> failed to set rax... reason = %d\n", err );
return;
}
}
else
{
if ( ( err = uc_mem_map( uc_ctx, module_base, module_size, UC_PROT_ALL ) ) )
{
std::printf( "> failed to load library... reason = %d\n", err );
return;
}
win::reloc_block_t *reloc_block = &reloc_dir->first_block;
while (reloc_block->base_rva && reloc_block->size_block)
reloc_block = reloc_block->next();
if ( ( err = uc_mem_write( uc_ctx, module_base, reinterpret_cast< void * >( module_base ), module_size ) ) )
{
std::printf( "> failed to copy module into emulator... reason = %d\n", err );
return;
}
reloc_block->base_rva = reloc_rva;
reloc_block->size_block =
relocs.size() * sizeof(win::reloc_entry_t) + sizeof(uint64_t);
if ( ( err = uc_reg_write( uc_ctx, UC_X86_REG_RAX, &module_base ) ) )
{
std::printf( "> failed to set rax... reason = %d\n", err );
return;
}
reloc_block->next()->base_rva = 0ull;
reloc_block->next()->size_block = 0ull;
obj->loaded_modules.push_back( module_base );
}
for (auto idx = 0u; idx < relocs.size(); ++idx) {
reloc_block->entries[idx].type = win::reloc_type_id::rel_based_dir64;
reloc_block->entries[idx].offset = relocs[idx];
}
void unpack_t::uc_strcpy( uc_engine *uc_ctx, char *buff, std::uintptr_t addr )
{
uc_err err;
char i = 0u;
auto idx = 0ul;
do
{
if ( ( err = uc_mem_read( uc_ctx, addr + idx, &i, sizeof i ) ) )
break;
} while ( ( buff[ idx++ ] = i ) );
}
return true;
}
void unpack_t::local_alloc_hook(uc_engine *uc_ctx, unpack_t *obj) {
uc_err err;
std::uintptr_t rax, rdx;
if ((err = uc_reg_read(uc_ctx, UC_X86_REG_RDX, &rdx))) {
std::printf("> failed to read RDX... reason = %d\n", rdx);
return;
}
auto size = ((rdx + PAGE_4KB) & ~0xFFFull);
if ((err = uc_mem_map(uc_ctx, HEAP_BASE + obj->heap_offset, size,
UC_PROT_ALL))) {
std::printf("> failed to allocate memory... reason = %d\n", err);
return;
}
rax = HEAP_BASE + obj->heap_offset;
obj->heap_offset += size;
if ((err = uc_reg_write(uc_ctx, UC_X86_REG_RAX, &rax))) {
std::printf("> failed to write rax... reason = %d\n", err);
return;
}
}
void unpack_t::local_free_hook(uc_engine *uc_ctx, unpack_t *obj) {
uc_err err;
std::uintptr_t rax = 0ull;
if ((err = uc_reg_write(uc_ctx, UC_X86_REG_RAX, &rax))) {
std::printf("> failed to write rax... reason = %d\n", err);
return;
}
}
void unpack_t::load_library_hook(uc_engine *uc_ctx, unpack_t *obj) {
uc_err err;
std::uintptr_t rcx = 0ull;
if ((err = uc_reg_read(uc_ctx, UC_X86_REG_RCX, &rcx))) {
std::printf("> uc_reg_read error, reason = %d\n", err);
return;
}
char buff[256];
uc_strcpy(uc_ctx, buff, rcx);
std::printf("> LoadLibraryA(\"%s\")\n", buff);
if (!obj->loaded_modules[buff]) {
std::vector<std::uint8_t> module_data, tmp;
if (!vm::util::open_binary_file(buff, module_data)) {
std::printf(
"[!] failed to open a dependency... please put %s in the same folder "
"as vmprofiler-cli...\n",
buff);
exit(-1);
}
bool unpack_t::iat_dispatcher( uc_engine *uc, uint64_t address, uint32_t size, unpack_t *unpack )
{
auto vec = address - IAT_VECTOR_TABLE;
for ( auto &[ iat_name, iat_hook_data ] : unpack->iat_hooks )
{
if ( iat_hook_data.first == vec )
{
std::printf( "> hooking import = %s\n", iat_name.c_str() );
iat_hook_data.second( uc, unpack );
return true;
}
}
return false;
auto img = reinterpret_cast<win::image_t<> *>(module_data.data());
auto image_size = img->get_nt_headers()->optional_header.size_image;
tmp.resize(image_size);
std::memcpy(tmp.data(), module_data.data(), 0x1000);
std::for_each(img->get_nt_headers()->get_sections(),
img->get_nt_headers()->get_sections() +
img->get_nt_headers()->file_header.num_sections,
[&](const auto &section_header) {
std::memcpy(
tmp.data() + section_header.virtual_address,
module_data.data() + section_header.ptr_raw_data,
section_header.size_raw_data);
});
const auto module_base = reinterpret_cast<std::uintptr_t>(tmp.data());
const auto image_base = img->get_nt_headers()->optional_header.image_base;
const auto alloc_addr = module_base & ~0x1000ull;
obj->loaded_modules[buff] = alloc_addr;
if ((err = uc_reg_write(uc_ctx, UC_X86_REG_RAX, &alloc_addr))) {
std::printf("> failed to set rax... reason = %d\n", err);
return;
}
bool unpack_t::code_exec_callback( uc_engine *uc, uint64_t address, uint32_t size, unpack_t *unpack )
{
static ZydisDecoder decoder;
static ZydisFormatter formatter;
static ZydisDecodedInstruction instr;
if ( static std::atomic< bool > once{ false }; !once.exchange( true ) )
{
ZydisDecoderInit( &decoder, ZYDIS_MACHINE_MODE_LONG_64, ZYDIS_ADDRESS_WIDTH_64 );
ZydisFormatterInit( &formatter, ZYDIS_FORMATTER_STYLE_INTEL );
}
auto instr_ptr = reinterpret_cast< void * >( unpack->map_bin.data() + ( address - unpack->img_base ) );
if ( ZYAN_SUCCESS( ZydisDecoderDecodeBuffer( &decoder, instr_ptr, PAGE_4KB, &instr ) ) )
{
if ( instr.mnemonic == ZYDIS_MNEMONIC_CALL && instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
instr.operands[ 0 ].reg.value == ZYDIS_REGISTER_RAX )
{
std::uintptr_t rax = 0u, rip = 0u;
uc_reg_read( uc, UC_X86_REG_RAX, &rax );
uc_reg_read( uc, UC_X86_REG_RIP, &rip );
if ( rax > unpack->img_base + unpack->img_size ) // skip calls to kernel32.dll...
{
rip += instr.length;
uc_reg_write( uc, UC_X86_REG_RIP, &rip );
}
}
}
return true;
} else {
const auto alloc_addr = obj->loaded_modules[buff];
if ((err = uc_reg_write(uc_ctx, UC_X86_REG_RAX, &alloc_addr))) {
std::printf("> failed to set rax... reason = %d\n", err);
return;
}
bool unpack_t::unpack_section_callback( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,
unpack_t *unpack )
{
if ( address == unpack->pack_section_offset + unpack->img_base )
{
std::printf( "> dumping...\n" );
uc_emu_stop( uc );
return false;
}
return true;
}
} // namespace engine
void unpack_t::uc_strcpy(uc_engine *uc_ctx, char *buff, std::uintptr_t addr) {
uc_err err;
char i = 0u;
auto idx = 0ul;
do {
if ((err = uc_mem_read(uc_ctx, addr + idx, &i, sizeof i))) break;
} while ((buff[idx++] = i));
}
bool unpack_t::iat_dispatcher(uc_engine *uc, uint64_t address, uint32_t size,
unpack_t *unpack) {
auto vec = address - IAT_VECTOR_TABLE;
for (auto &[iat_name, iat_hook_data] : unpack->iat_hooks) {
if (iat_hook_data.first == vec) {
std::printf("> hooking import = %s\n", iat_name.c_str());
iat_hook_data.second(uc, unpack);
return true;
}
void unpack_t::invalid_mem( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,
unpack_t *unpack )
{
switch ( type )
{
case UC_MEM_READ_UNMAPPED:
std::printf( ">>> reading invalid memory at address = 0x%p, size = 0x%x\n", address, size );
break;
case UC_MEM_WRITE_UNMAPPED:
std::printf( ">>> writing invalid memory at address = 0x%p, size = 0x%x, val = 0x%x\n", address, size,
value );
break;
case UC_MEM_FETCH_UNMAPPED:
{
std::printf( ">>> fetching invalid instructions at address = 0x%p\n", address );
break;
}
default:
break;
}
}
return false;
}
bool unpack_t::code_exec_callback(uc_engine *uc, uint64_t address,
uint32_t size, unpack_t *unpack) {
static ZydisDecoder decoder;
static ZydisFormatter formatter;
static ZydisDecodedInstruction instr;
if (static std::atomic<bool> once{false}; !once.exchange(true)) {
ZydisDecoderInit(&decoder, ZYDIS_MACHINE_MODE_LONG_64,
ZYDIS_ADDRESS_WIDTH_64);
ZydisFormatterInit(&formatter, ZYDIS_FORMATTER_STYLE_INTEL);
}
auto instr_ptr = reinterpret_cast<void *>(unpack->map_bin.data() +
(address - unpack->img_base));
if (ZYAN_SUCCESS(
ZydisDecoderDecodeBuffer(&decoder, instr_ptr, PAGE_4KB, &instr))) {
if (instr.mnemonic == ZYDIS_MNEMONIC_CALL &&
instr.operands[0].type == ZYDIS_OPERAND_TYPE_REGISTER &&
instr.operands[0].reg.value == ZYDIS_REGISTER_RAX) {
std::uintptr_t rax = 0u, rip = 0u;
uc_reg_read(uc, UC_X86_REG_RAX, &rax);
uc_reg_read(uc, UC_X86_REG_RIP, &rip);
if (rax > unpack->img_base + unpack->img_size ||
rax < unpack->img_base) // skip calls to kernel32.dll...
{
rip += instr.length;
uc_reg_write(uc, UC_X86_REG_RIP, &rip);
}
}
}
return true;
}
bool unpack_t::unpack_section_callback(uc_engine *uc, uc_mem_type type,
uint64_t address, int size,
int64_t value, unpack_t *unpack) {
if (address == unpack->pack_section_offset + unpack->img_base) {
std::printf("> dumping...\n");
uc_emu_stop(uc);
return false;
}
return true;
}
void unpack_t::invalid_mem(uc_engine *uc, uc_mem_type type, uint64_t address,
int size, int64_t value, unpack_t *unpack) {
switch (type) {
case UC_MEM_READ_UNMAPPED:
std::printf(">>> reading invalid memory at address = 0x%p, size = 0x%x\n",
address, size);
break;
case UC_MEM_WRITE_UNMAPPED:
std::printf(
">>> writing invalid memory at address = 0x%p, size = 0x%x, val = "
"0x%x\n",
address, size, value);
break;
case UC_MEM_FETCH_UNMAPPED: {
std::printf(">>> fetching invalid instructions at address = 0x%p\n",
address);
break;
}
} // namespace engine
default:
break;
}
}
} // namespace engine

1238
src/vmemu_t.cpp
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