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vmprofiler/src/vmhandler.cpp

399 lines
13 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;
for (auto& instr : vprofile->signature)
{
const auto contains = std::find_if
(
vm_handler->instrs.begin(),
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);
}
}
}
}