Patched Code

Hooksware (Volume 2, page 63) pattern originally came from memory dump analysis pattern catalog and is too general for malware analysis pattern catalog. So we decided to factor out 3 separate patterns. The first one includes cases such as in-place patching:

0:004> u ntdll!ZwQueryDirectoryFile
ntdll!ZwQueryDirectoryFile:
77814db4 b8da000000      mov     eax,0DAh
77814db9 bae8af0500      mov     edx,5AFE8h
77814dbe ff12            call    dword ptr [edx]
77814dc0 c22c00          ret     2Ch
77814dc3 90              nop
ntdll!NtQueryDirectoryObject:
77814dc4 b8db000000      mov     eax,0DBh
77814dc9 ba0003fe7f      mov     edx,offset SharedUserData!SystemCallStub
(7ffe0300)
77814dce ff12            call    dword ptr [edx]

And detour patching:

0:004> u wininet!InternetReadFile
wininet!InternetReadFile:
7758654b e98044ac88      jmp     0004a9d0
77586550 83ec24          sub     esp,24h
77586553 53              push    ebx
77586554 56              push    esi
77586555 57              push    edi
77586556 33ff            xor     edi,edi
77586558 393db8116277    cmp     dword ptr [wininet!GlobalDataInitialized
(776211b8)],edi
7758655e 897df4          mov     dword ptr [ebp-0Ch],edi

In case of WinDbg such pattern is usually detected on the crash spot such as from RIP Stack Trace (page 244) or from !chkimg command output.