RE: WebDav Exploit ffs

From: Exurity Debugs (exbugsat_private)
Date: Thu Mar 27 2003 - 14:02:53 PST

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    I don't believe your shell code will work on other Kernel32.dll than the
    version with the following ImageBase:
    "\x00\x00\xe7\x77" // offsets of kernel32.dll for some win ver..
    
    Because your code is reversed as:
    
    loc_8F:
        mov     eax, [esi]
        add     eax, ebp
        cmp     dword ptr [eax], 50746547h
        jnz     short loc_C0
        cmp     dword ptr [eax+4], 41636F72h
        jnz     short loc_C0
        cmp     dword ptr [eax+8], 65726464h
        jnz     short loc_C0
        mov     eax, [edi+24h]
        add     eax, ebp
        movzx   ebx, word ptr [eax+edx*2]
        mov     eax, [edi+1Ch]
        add     eax, ebp
        mov     ebx, [eax+ebx*4]
        add     ebx, ebp
    
            ; should jump to found
    loc_C0:
        add     esi, 4
        inc     edx
        cmp     edx, [edi+18h]
        jnz     short loc_8F
            ; then reached all and could not find, so find another version
    So, if the Kernel32.dll happens to be different than the default, it will
    simply crash without going too far.
    Best regards
    Peter Huang
    Jumpable, Callable & Overflowing XPoson, New Exploitation Technology on the
    way
    



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