Function at 0x500a40
Capabilities:
Clear file content
Encode data using xor
Get hostname
Get session user name
Query or enumerate registry value
Set registry value
Write file on windows

Disassembly:
sub esp, 0x2b4
push ebx
push ebp
push esi
push edi
push 0x5500d4
mov dword [esp + 0x2c], ecx
lea esi, [ecx + 0x28]
call fcn.005049d0
add esp, 4
push eax
push esi
call fcn.004ffbe0
add esp, 8
lea eax, [esp + 0x24]
lea ecx, [esp + 0x18]
mov dword [esp + 0x10], 0
push eax
push ecx
push 0
push 0xf003f
push 0
push 0
push 0
push 0x55009c
xor bl, bl
call fcn.005049d0
add esp, 4
push eax
push reloc.DSOUND.dll_DirectSoundCreate
call dword [sym.imp.ADVAPI32.dll_RegCreateKeyExA]
test eax, eax
jne 0x500bdf
mov eax, dword [esp + 0x24]
mov edi, dword [sym.imp.USER32.dll_wsprintfA]
cmp eax, 2
jne 0x500b51
lea edx, [esp + 0x14]
lea eax, [esp + 0x40]
push edx
push eax
push 0
push 0
push 0x550088
mov dword [esp + 0x28], 0x40
call fcn.005049d0
mov ecx, dword [esp + 0x2c]
mov ebp, dword [sym.imp.ADVAPI32.dll_RegQueryValueExA]
add esp, 4
push eax
push ecx
call ebp
push str.Thu_Mar_17_14:23:26_2005
lea edx, [esp + 0x84]
push 0x550084
push edx
call edi
mov eax, dword [esp + 0x20]
add esp, 0xc
test eax, eax
je 0x500b26
lea eax, [esp + 0x80]
lea ecx, [esp + 0x40]
push eax
push ecx
call dword [sym.imp.KERNEL32.dll_lstrcmpA]
test eax, eax
jne 0x500b26
mov bl, 1
lea edx, [esp + 0x14]
lea eax, [esp + 0x10]
push edx
push eax
push 0
push 0
push 0x550074
mov dword [esp + 0x28], 4
call fcn.005049d0
mov ecx, dword [esp + 0x2c]
add esp, 4
push eax
push ecx
call ebp
push str.Thu_Mar_17_14:23:26_2005
lea edx, [esp + 0x44]
push 0x550084
push edx
call edi
add esp, 0xc
lea eax, [esp + 0x40]
push eax
call dword [sym.imp.KERNEL32.dll_lstrlenA]
inc eax
lea ecx, [esp + 0x40]
push eax
push ecx
push 1
push 0
push 0x550060
mov dword [esp + 0x28], eax
call fcn.005049d0
mov edx, dword [esp + 0x2c]
mov edi, dword [sym.imp.ADVAPI32.dll_RegSetValueExA]
add esp, 4
push eax
push edx
call edi
test bl, bl
mov dword [esp + 0x14], 4
je 0x500bac
inc dword [esp + 0x10]
jmp 0x500bb4
mov dword [esp + 0x10], 0
lea eax, [esp + 0x10]
push 4
push eax
push 4
push 0
push 0x550074
call fcn.005049d0
mov ecx, dword [esp + 0x2c]
add esp, 4
push eax
push ecx
call edi
mov edx, dword [esp + 0x18]
push edx
call dword [sym.imp.ADVAPI32.dll_RegCloseKey]
mov eax, dword [esp + 0x10]
cmp eax, 1
je 0x50102a
cmp eax, 5
ja 0x50102a
test bl, bl
je 0x500c06
cmp dword [0xec6324], 9
jge 0x50102a
push 0x550050
call fcn.005049d0
add esp, 4
push eax
push esi
call fcn.004ffbe0
mov eax, dword [esi]
add esp, 8
cmp eax, 0xffffffff
je 0x500d59
lea edi, [esi + 0x101c]
push edi
call dword [sym.imp.KERNEL32.dll_GetLocalTime]
mov eax, dword [esi + 0x1034]
test eax, eax
je 0x500c4e
mov ecx, dword [esi + 0x1038]
cmp ecx, eax
mov eax, 0x54f3d8
ja 0x500c53
mov eax, 0x5550b8
push eax
xor eax, eax
mov ax, word [esi + 0x102a]
xor ecx, ecx
mov cx, word [esi + 0x1028]
push eax
xor edx, edx
xor eax, eax
mov dx, word [esi + 0x1026]
mov ax, word [esi + 0x1024]
push ecx
push edx
xor ecx, ecx
push eax
mov cx, word [esi + 0x1022]
xor edx, edx
mov dx, word [esi + 0x101e]
xor eax, eax
mov ax, word [edi]
push ecx
push edx
push eax
push 0x54f380
lea ebp, [esi + 0x1c]
call fcn.00504960
add esp, 4
push eax
push ebp
call fcn.0050543d
mov edi, ebp
or ecx, 0xffffffff
xor eax, eax
add esp, 0x28
repne scasb al, byte es:[edi]
mov eax, dword [esi + 0x1030]
not ecx
dec ecx
test eax, eax
je 0x500cf5
test ecx, ecx
jle 0x500d23
mov edi, 0xffffffe4
mov eax, ebp
sub edi, esi
mov edx, dword [esi + 0x1030]
add edx, 2
mov dword [esi + 0x1030], edx
mov bl, byte [eax]
add dl, 0x43
xor bl, dl
mov byte [eax], bl
inc eax
lea edx, [edi + eax]
cmp edx, ecx
jl 0x500cd3
jmp 0x500d23
test ecx, ecx
jle 0x500d23
mov edi, 0xffffffe4
mov eax, ebp
sub edi, esi
mov edx, dword [esi + 0x102c]
lea edx, [edx + edx*2 + 1]
mov dword [esi + 0x102c], edx
mov bl, byte [eax]
add dl, 0x65
xor bl, dl
mov byte [eax], bl
inc eax
lea edx, [eax + edi]
cmp edx, ecx
jl 0x500d02
cmp dword [esi + 0x1034], 0x3e7
je 0x500d41
lea eax, [esp + 0x20]
push 0
push eax
push ecx
mov ecx, dword [esi]
push ebp
push ecx
call dword [sym.imp.KERNEL32.dll_WriteFile]
mov edx, dword [esi]
push edx
call dword [sym.imp.KERNEL32.dll_SetEndOfFile]
mov eax, dword [esi]
push eax
call dword [sym.imp.KERNEL32.dll_CloseHandle]
mov dword [esi], 0xffffffff
mov ecx, 0xec6110
call fcn.00503130
test eax, eax
jne 0x500d87
push 0x550040
call fcn.005049d0
add esp, 4
mov ecx, 0xec6110
push eax
call fcn.00502f20
test eax, eax
je 0x50102a
push 0x55002c
call fcn.005049d0
add esp, 4
mov ecx, 0xec6110
push eax
call fcn.00503130
push eax
call fcn.00501dd0
push 0x550014
mov esi, eax
call fcn.005049d0
add esp, 4
mov ecx, 0xec6110
push eax
call fcn.00503130
push eax
call fcn.00501dd0
push 0x54fffc
mov edi, eax
call fcn.005049d0
add esp, 4
mov ecx, 0xec6110
push eax
call fcn.00503130
push eax
call fcn.00501dd0
push 0x54ffec
mov ebp, eax
call fcn.005049d0
add esp, 4
mov ecx, 0xec6110
push eax
call fcn.00503130
push eax
call fcn.00501dd0
test esi, esi
mov dword [esp + 0x20], eax
je 0x50102a
test edi, edi
je 0x50102a
test ebp, ebp
je 0x50102a
test eax, eax
je 0x50102a
push 0
push 0
push 0
push 0
push 0x54ffe0
call fcn.00504960
add esp, 4
push eax
call esi
mov ebx, eax
test ebx, ebx
je 0x50102a
push 0
push 0x8000000
push 1
push 0x54ffac
call fcn.005049d0
add esp, 4
push eax
push 0x54ffa0
call fcn.00504960
add esp, 4
push eax
push 0x17ac
push 0x54ff8c
call fcn.00504960
add esp, 4
push eax
push ebx
call edi
mov esi, eax
test esi, esi
jne 0x500e9a
push ebx
call ebp
pop edi
pop esi
pop ebp
pop ebx
add esp, 0x2b4
ret
lea ecx, [esp + 0x1c]
lea edx, [esp + 0x140]
mov edi, 0x80
push ecx
push edx
mov byte [esp + 0x148], 0
mov dword [esp + 0x24], edi
call dword [sym.imp.KERNEL32.dll_GetComputerNameA]
lea eax, [esp + 0x1c]
lea ecx, [esp + 0xc0]
push eax
push ecx
mov byte [esp + 0xc8], 0
mov dword [esp + 0x24], edi
call dword [sym.imp.ADVAPI32.dll_GetUserNameA]
lea edx, [esp + 0x2c]
push edx
call dword [sym.imp.KERNEL32.dll_GetLocalTime]
mov eax, dword [0xec6324]
cmp eax, 1
jne 0x500ef9
push 0x54ff80
jmp 0x500f5e
cmp eax, 2
jne 0x500f05
push 0x54ff74
jmp 0x500f5e
cmp eax, 3
jne 0x500f11
push 0x54ff6c
jmp 0x500f5e
cmp eax, 4
jne 0x500f1d
push 0x54ff60
jmp 0x500f5e
cmp eax, 5
jne 0x500f29
push 0x54ff54
jmp 0x500f5e
cmp eax, 6
jne 0x500f35
push 0x54ff44
jmp 0x500f5e
cmp eax, 7
jne 0x500f41
push 0x54ff38
jmp 0x500f5e
cmp eax, 8
jne 0x500f4d
push 0x54ff2c
jmp 0x500f5e
cmp eax, 9
jne 0x500f59
push 0x54ff20
jmp 0x500f5e
push 0x54ff18
call fcn.00504960
mov ecx, dword [esp + 0x3e]
mov edx, dword [esp + 0x3c]
add esp, 4
and ecx, 0xffff
and edx, 0xffff
push ecx
mov ecx, dword [esp + 0x3a]
and ecx, 0xffff
push edx
mov edx, dword [esp + 0x3c]
push ecx
mov ecx, dword [esp + 0x3e]
and edx, 0xffff
and ecx, 0xffff
push edx
mov edx, dword [esp + 0x3e]
push ecx
mov ecx, dword [esp + 0x40]
and edx, 0xffff
and ecx, 0xffff
push edx
push ecx
mov ecx, dword [esp + 0x44]
lea edx, [ecx + 0x1230]
add ecx, 0x1208
push edx
lea edx, [esp + 0xe0]
push edx
lea edx, [esp + 0x164]
push edx
mov edx, dword [0xec6350]
mov edx, dword [edx + 0x10]
push edx
push eax
push 0x2d
push ecx
push 0x54febc
call fcn.005049d0
add esp, 4
push eax
lea eax, [esp + 0x1fc]
push 0x104
push eax
call fcn.00506bfd
add esp, 0x44
lea ecx, [esp + 0x1c0]
push 0
push 0x4000002
push ecx
push 0xec6004
push esi
call dword [esp + 0x34]
call dword [sym.imp.KERNEL32.dll_GetLastError]
push ebx
call ebp
push esi
call ebp
pop edi
pop esi
pop ebp
pop ebx
add esp, 0x2b4
ret