scdbg fopen mode


Author: David Zimmer
Date: 03.08.11 - 4:58pm



Added a new option to scdbg the other day that allows it to work with file format shellcode that scans for open file handles using GetFileSize().

When ReadFile is called the -fopen mode allows the shellcode to actually access data within the target file. If you add the -i interactive mode as well, then the retrieved (and probably decoded) buffers are then written to disk as a randomly named tmp file when a write api is called.

All in all pretty painless capture of decoded and dropped executables!
$ ./sctest -f test.sc -fopen bad.pdf -s -1 -i
fopen(bad.pdf) = 4d565c
Loaded 312 bytes from file test.sc
Initilization Complete..
Interactive Hooks enabled
Max Steps: -1
Using base offset: 0x401000

401083  GetFileSize(4) = 2031b
401112  GlobalAlloc(sz=2031b) = 60000
401118  SetFilePointer(hFile=4, dist=0, FILE_BEGIN)
401132  ReadFile(hFile=4, buf=60000, numBytes=2031b)
401147  CreateFile(x.exe)
        Interactive mode local file: /tmp/WHhUmhtM
401158  WriteFile()
401176  WinExec(x.exe)

Couple other updates include:
exe - added hooks for SetFilePointer, ReadFile, strstr, 
      strtoul, FreeLibrary, GlobalFree, GetCurrentProcess, 
      TerminateProcess
      /bp and /laa now accept api names to break at
dll - enabled support for TEST A8 and A9 (seems ok but need more testing..)
updated binaries and source uploaded.




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