Function at 0x421000
Capabilities:
Allocate or change rwx memory
Execute shellcode via indirect call
Hook routines via microsoft detours

Disassembly:
sub esp, 0x20
push ebx
push ebp
push esi
mov esi, dword [esp + 0x30]
cmp esi, 0x7ff80000
push edi
jbe 0x42101f
lea ebx, [esi - 0x7ff80000]
mov dword [esp + 0x34], ebx
jmp 0x42102b
mov dword [esp + 0x34], 0x10000
mov ebx, dword [esp + 0x34]
cmp esi, 0x80000000
jae 0x42103f
lea edi, [esi + 0x7ff80000]
mov dword [esp + 0x10], edi
jmp 0x42104b
mov dword [esp + 0x10], 0xfff80000
mov edi, dword [esp + 0x10]
mov eax, dword [0x437fd0]
mov edx, dword [0x437fcc]
test eax, eax
jne 0x421065
test edx, edx
je 0x421078
mov eax, edx
mov dword [0x437fd0], eax
mov ecx, dword [eax + 8]
test ecx, ecx
je 0x421078
cmp ecx, ebx
jb 0x421078
cmp ecx, edi
jbe 0x421203
mov eax, edx
test edx, edx
mov dword [0x437fd0], eax
je 0x4210a6
test eax, eax
je 0x42109a
mov ecx, dword [eax + 8]
test ecx, ecx
je 0x42109a
cmp ecx, ebx
jb 0x42109a
cmp ecx, edi
jbe 0x421203
mov eax, dword [eax + 4]
test eax, eax
mov dword [0x437fd0], eax
jne 0x421087
mov ebp, dword [sym.imp.KERNEL32.dll_VirtualQuery]
mov eax, esi
and eax, 0xffff
sub esi, eax
cmp esi, ebx
mov ebx, dword [sym.imp.KERNEL32.dll_VirtualAlloc]
mov edi, esi
jbe 0x421123
cmp edi, 0x70000000
jb 0x4210d6
cmp edi, 0x80000000
ja 0x4210d6
mov edi, 0x6fff0000
lea ecx, [esp + 0x14]
push 0x1c
push ecx
push edi
call ebp
test eax, eax
je 0x421123
mov ecx, dword [esp + 0x24]
mov eax, 0x10000
cmp ecx, eax
jne 0x4210f7
cmp dword [esp + 0x20], eax
jae 0x42110b
mov edx, dword [esp + 0x18]
mov eax, dword [esp + 0x34]
lea edi, [edx - 0x10000]
cmp edi, eax
ja 0x4210c1
jmp 0x421123
push 0x40
push 0x3000
push eax
push edi
call ebx
test eax, eax
mov dword [0x437fd0], eax
jne 0x4211b0
mov edi, dword [esp + 0x10]
cmp esi, edi
jae 0x4211a6
cmp esi, 0x70000000
jb 0x421140
cmp esi, 0x80000000
ja 0x421140
mov esi, 0x80010000
lea eax, [esp + 0x14]
push 0x1c
push eax
push esi
call ebp
test eax, eax
je 0x4211a6
mov eax, dword [esp + 0x24]
mov edx, 0x10000
cmp eax, edx
jne 0x421197
cmp dword [esp + 0x20], edx
jb 0x421197
mov ecx, esi
and ecx, 0xffff
je 0x421183
mov esi, dword [esp + 0x20]
mov eax, edx
sub eax, ecx
sub esi, eax
mov dword [esp + 0x20], esi
mov esi, dword [esp + 0x14]
add esi, eax
mov dword [esp + 0x14], esi
push 0x40
push 0x3000
push edx
push esi
call ebx
test eax, eax
mov dword [0x437fd0], eax
jne 0x4211b0
mov ecx, dword [esp + 0x14]
mov edx, dword [esp + 0x20]
lea esi, [ecx + edx]
cmp esi, edi
jb 0x42112b
pop edi
pop esi
pop ebp
xor eax, eax
pop ebx
add esp, 0x20
ret
mov dword [eax], 0x52727464
mov eax, dword [0x437fd0]
xor ecx, ecx
mov dword [eax + 8], ecx
mov edx, dword [0x437fd0]
mov eax, dword [0x437fcc]
mov dword [edx + 4], eax
mov eax, dword [0x437fd0]
mov dword [0x437fcc], eax
add eax, 0xffcc
mov edx, 0x719
mov dword [eax + 0x18], ecx
mov ecx, eax
sub eax, 0x24
dec edx
jne 0x4211e2
mov edx, dword [0x437fd0]
mov ebx, dword [esp + 0x34]
mov edi, dword [esp + 0x10]
mov dword [edx + 8], ecx
mov eax, dword [0x437fd0]
mov edx, dword [eax + 8]
cmp edx, ebx
jb 0x4211a6
cmp edx, edi
ja 0x4211a6
mov ecx, dword [edx + 0x18]
mov edi, edx
mov dword [eax + 8], ecx
mov ecx, 9
mov eax, 0xcccccccc
rep stosd dword es:[edi], eax
pop edi
pop esi
pop ebp
mov eax, edx
pop ebx
add esp, 0x20
ret