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vmprofiler/src/vmhandler.cpp

350 lines
16 KiB

#include <vmprofiler.hpp>
namespace vm
{
namespace handler
{
bool get( zydis_routine_t &calc_jmp, zydis_routine_t &vm_handler, std::uintptr_t handler_addr )
{
if ( !vm::util::flatten( vm_handler, handler_addr ) )
return false;
vm::util::deobfuscate( vm_handler );
static const auto calc_jmp_check = [ & ]( std::uintptr_t addr ) -> bool {
for ( const auto &[ instr, instr_raw, instr_addr ] : calc_jmp )
if ( instr_addr == addr )
return true;
return false;
};
auto result = std::find_if( vm_handler.begin(), vm_handler.end(), []( const zydis_instr_t &instr ) -> bool {
if ( instr.instr.mnemonic == ZYDIS_MNEMONIC_LEA &&
instr.instr.operands[ 0 ].reg.value == ZYDIS_REGISTER_RAX &&
instr.instr.operands[ 1 ].mem.base == ZYDIS_REGISTER_RDI &&
instr.instr.operands[ 1 ].mem.disp.value == 0xE0 )
return true;
return calc_jmp_check( instr.addr );
} );
// remove calc_jmp from the vm handler vector...
if ( result != vm_handler.end() )
vm_handler.erase( result, vm_handler.end() );
else // locate the last mov al, [rsi],
// then remove all instructions after that...
{
zydis_routine_t::iterator last = vm_handler.end();
result = vm_handler.begin();
while ( result != vm_handler.end() )
{
result = std::find_if( ++result, vm_handler.end(), []( const zydis_instr_t &instr_data ) -> bool {
// mov/movsx/movzx rax/eax/ax/al, [rsi]
if ( instr_data.instr.operand_count > 1 &&
( instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOV ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVSX ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVZX ) &&
instr_data.instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
util::reg::to64( instr_data.instr.operands[ 0 ].reg.value ) == ZYDIS_REGISTER_RAX &&
instr_data.instr.operands[ 1 ].type == ZYDIS_OPERAND_TYPE_MEMORY &&
instr_data.instr.operands[ 1 ].mem.base == ZYDIS_REGISTER_RSI )
return true;
return false;
} );
if ( result != vm_handler.end() )
last = result;
}
if ( last != vm_handler.end() )
vm_handler.erase( last, vm_handler.end() );
}
return true;
}
bool get_all( std::uintptr_t module_base, std::uintptr_t image_base, zydis_routine_t &vm_entry,
std::uintptr_t *vm_handler_table, std::vector< vm::handler::handler_t > &vm_handlers )
{
zydis_decoded_instr_t instr;
if ( !vm::handler::table::get_transform( vm_entry, &instr ) )
return false;
zydis_routine_t calc_jmp;
if ( !vm::calc_jmp::get( vm_entry, calc_jmp ) )
return false;
for ( auto idx = 0u; idx < 256; ++idx )
{
const auto decrypt_val = vm::handler::table::decrypt( instr, vm_handler_table[ idx ] );
handler_t vm_handler;
vm::transform::map_t transforms;
zydis_routine_t vm_handler_instrs;
if ( !vm::handler::get( calc_jmp, vm_handler_instrs, ( decrypt_val - image_base ) + module_base ) )
return false;
const auto has_imm = vm::handler::has_imm( vm_handler_instrs );
const auto imm_size = vm::handler::imm_size( vm_handler_instrs );
if ( has_imm && !vm::handler::get_operand_transforms( vm_handler_instrs, transforms ) )
return false;
vm_handler.address = ( decrypt_val - image_base ) + module_base;
vm_handler.instrs = vm_handler_instrs;
vm_handler.imm_size = imm_size;
vm_handler.transforms = transforms;
vm_handler.profile = vm::handler::get_profile( vm_handler );
vm_handlers.push_back( vm_handler );
}
return true;
}
bool has_imm( const zydis_routine_t &vm_handler )
{
const auto result =
std::find_if( vm_handler.begin(), vm_handler.end(), []( const zydis_instr_t &instr_data ) -> bool {
// mov/movsx/movzx rax/eax/ax/al, [rsi]
if ( instr_data.instr.operand_count > 1 &&
( instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOV ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVSX ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVZX ) &&
instr_data.instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
util::reg::to64( instr_data.instr.operands[ 0 ].reg.value ) == ZYDIS_REGISTER_RAX &&
instr_data.instr.operands[ 1 ].type == ZYDIS_OPERAND_TYPE_MEMORY &&
instr_data.instr.operands[ 1 ].mem.base == ZYDIS_REGISTER_RSI )
return true;
return false;
} );
return result != vm_handler.end();
}
std::uint8_t imm_size( const zydis_routine_t &vm_handler )
{
const auto result =
std::find_if( vm_handler.begin(), vm_handler.end(), []( const zydis_instr_t &instr_data ) -> bool {
// mov/movsx/movzx rax/eax/ax/al, [rsi]
if ( instr_data.instr.operand_count > 1 &&
( instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOV ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVSX ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVZX ) &&
instr_data.instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
util::reg::to64( instr_data.instr.operands[ 0 ].reg.value ) == ZYDIS_REGISTER_RAX &&
instr_data.instr.operands[ 1 ].type == ZYDIS_OPERAND_TYPE_MEMORY &&
instr_data.instr.operands[ 1 ].mem.base == ZYDIS_REGISTER_RSI )
return true;
return false;
} );
if ( result == vm_handler.end() )
return 0u;
return result->instr.operands[ 1 ].size;
}
bool get_operand_transforms( const zydis_routine_t &vm_handler, transform::map_t &transforms )
{
auto imm_fetch =
std::find_if( vm_handler.begin(), vm_handler.end(), []( const zydis_instr_t &instr_data ) -> bool {
// mov/movsx/movzx rax/eax/ax/al, [rsi]
if ( instr_data.instr.operand_count > 1 &&
( instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOV ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVSX ||
instr_data.instr.mnemonic == ZYDIS_MNEMONIC_MOVZX ) &&
instr_data.instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
util::reg::to64( instr_data.instr.operands[ 0 ].reg.value ) == ZYDIS_REGISTER_RAX &&
instr_data.instr.operands[ 1 ].type == ZYDIS_OPERAND_TYPE_MEMORY &&
instr_data.instr.operands[ 1 ].mem.base == ZYDIS_REGISTER_RSI )
return true;
return false;
} );
if ( imm_fetch == vm_handler.end() )
return false;
// this finds the first transformation which looks like:
// transform rax, rbx <--- note these registers can be smaller so we to64 them...
auto key_transform =
std::find_if( imm_fetch, vm_handler.end(), []( const zydis_instr_t &instr_data ) -> bool {
if ( util::reg::compare( instr_data.instr.operands[ 0 ].reg.value, ZYDIS_REGISTER_RAX ) &&
util::reg::compare( instr_data.instr.operands[ 1 ].reg.value, ZYDIS_REGISTER_RBX ) )
return true;
return false;
} );
if ( key_transform == vm_handler.end() )
return false;
// look for a primer/instruction that alters RAX prior to the 5 transformations...
auto generic0 = std::find_if( imm_fetch + 1, key_transform, []( const zydis_instr_t &instr_data ) -> bool {
return util::reg::compare( instr_data.instr.operands[ 0 ].reg.value, ZYDIS_REGISTER_RAX ) &&
!util::reg::compare( instr_data.instr.operands[ 1 ].reg.value, ZYDIS_REGISTER_RBX );
} );
zydis_decoded_instr_t nogeneric0;
nogeneric0.mnemonic = ZYDIS_MNEMONIC_INVALID;
transforms[ transform::type::generic0 ] = generic0 != key_transform ? generic0->instr : nogeneric0;
// last transformation is the same as the first except src and dest are swwapped...
transforms[ transform::type::rolling_key ] = key_transform->instr;
auto instr_copy = key_transform->instr;
instr_copy.operands[ 0 ].reg.value = key_transform->instr.operands[ 1 ].reg.value;
instr_copy.operands[ 1 ].reg.value = key_transform->instr.operands[ 0 ].reg.value;
transforms[ transform::type::update_key ] = instr_copy;
// three generic transformations...
auto generic_transform = key_transform;
for ( auto idx = 2u; idx < 5; ++idx )
{
generic_transform =
std::find_if( ++generic_transform, vm_handler.end(), []( const zydis_instr_t &instr_data ) -> bool {
if ( util::reg::compare( instr_data.instr.operands[ 0 ].reg.value, ZYDIS_REGISTER_RAX ) )
return true;
return false;
} );
if ( generic_transform == vm_handler.end() )
return false;
transforms[ ( transform::type )( idx ) ] = generic_transform->instr;
}
return true;
}
vm::handler::profile_t *get_profile( handler_t &vm_handler )
{
static const auto vcontains = []( vm::handler::profile_t *vprofile, handler_t *vm_handler ) -> bool {
if ( vprofile->imm_size != vm_handler->imm_size )
return false;
zydis_routine_t::iterator contains = vm_handler->instrs.begin();
for ( auto &instr : vprofile->signature )
{
contains = std::find_if(contains, vm_handler->instrs.end(),
[ & ]( zydis_instr_t &instr_data ) -> bool { return instr( instr_data.instr ); } );
if ( contains == vm_handler->instrs.end() )
return false;
}
return true;
};
for ( auto profile : vm::handler::profile::all )
if ( vcontains( profile, &vm_handler ) )
return profile;
return nullptr;
}
namespace table
{
std::uintptr_t *get( const zydis_routine_t &vm_entry )
{
const auto result =
std::find_if( vm_entry.begin(), vm_entry.end(), []( const zydis_instr_t &instr_data ) -> bool {
const auto instr = &instr_data.instr;
// lea r12, vm_handlers... (always r12)...
if ( instr->mnemonic == ZYDIS_MNEMONIC_LEA &&
instr->operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
instr->operands[ 0 ].reg.value == ZYDIS_REGISTER_R12 &&
!instr->raw.sib.base ) // no register used for the sib base...
return true;
return false;
} );
if ( result == vm_entry.end() )
return nullptr;
std::uintptr_t ptr = 0u;
ZydisCalcAbsoluteAddress( &result->instr, &result->instr.operands[ 1 ], result->addr, &ptr );
return reinterpret_cast< std::uintptr_t * >( ptr );
}
bool get_transform( const zydis_routine_t &vm_entry, zydis_decoded_instr_t *transform_instr )
{
zydis_register_t rcx_or_rdx = ZYDIS_REGISTER_NONE;
auto handler_fetch =
std::find_if( vm_entry.begin(), vm_entry.end(), [ & ]( const zydis_instr_t &instr_data ) -> bool {
const auto instr = &instr_data.instr;
if ( instr->mnemonic == ZYDIS_MNEMONIC_MOV && instr->operand_count == 2 &&
instr->operands[ 1 ].type == ZYDIS_OPERAND_TYPE_MEMORY &&
instr->operands[ 1 ].mem.base == ZYDIS_REGISTER_R12 &&
instr->operands[ 1 ].mem.index == ZYDIS_REGISTER_RAX &&
instr->operands[ 1 ].mem.scale == 8 &&
instr->operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
( instr->operands[ 0 ].reg.value == ZYDIS_REGISTER_RDX ||
instr->operands[ 0 ].reg.value == ZYDIS_REGISTER_RCX ) )
{
rcx_or_rdx = instr->operands[ 0 ].reg.value;
return true;
}
return false;
} );
// check to see if we found the fetch instruction and if the next instruction
// is not the end of the vector...
if ( handler_fetch == vm_entry.end() || ++handler_fetch == vm_entry.end() ||
// must be RCX or RDX... else something went wrong...
( rcx_or_rdx != ZYDIS_REGISTER_RCX && rcx_or_rdx != ZYDIS_REGISTER_RDX ) )
return false;
// find the next instruction that writes to RCX or RDX...
// the register is determined by the vm handler fetch above...
auto handler_transform =
std::find_if( handler_fetch, vm_entry.end(), [ & ]( const zydis_instr_t &instr_data ) -> bool {
if ( instr_data.instr.operands[ 0 ].reg.value == rcx_or_rdx &&
instr_data.instr.operands[ 0 ].actions & ZYDIS_OPERAND_ACTION_WRITE )
return true;
return false;
} );
if ( handler_transform == vm_entry.end() )
return false;
*transform_instr = handler_transform->instr;
return true;
}
std::uint64_t encrypt( zydis_decoded_instr_t &transform_instr, std::uint64_t val )
{
assert( transform_instr.operands[ 0 ].size == 64,
"invalid transformation for vm handler table entries..." );
const auto operation = vm::transform::inverse[ transform_instr.mnemonic ];
const auto bitsize = transform_instr.operands[ 0 ].size;
const auto imm =
vm::transform::has_imm( &transform_instr ) ? transform_instr.operands[ 1 ].imm.value.u : 0u;
return vm::transform::apply( bitsize, operation, val, imm );
}
std::uint64_t decrypt( zydis_decoded_instr_t &transform_instr, std::uint64_t val )
{
assert( transform_instr.operands[ 0 ].size == 64,
"invalid transformation for vm handler table entries..." );
const auto operation = transform_instr.mnemonic;
const auto bitsize = transform_instr.operands[ 0 ].size;
const auto imm =
vm::transform::has_imm( &transform_instr ) ? transform_instr.operands[ 1 ].imm.value.u : 0u;
return vm::transform::apply( bitsize, operation, val, imm );
}
} // namespace table
} // namespace handler
} // namespace vm