Cisco Systems has been trying to reproduce a PIX firewall
security hole outlined by a researcher during the Black Hat USA
2006 conference in Las Vegas earlier this month. So far,
the company has been unsuccessful.
Hendrik Scholz, lead VoIP developer and systems engineer with
Freenet Cityline of Germany,
announced the existence of the flaw at the
end of his presentation on SIP stack fingerprinting and attacks.
His final slide appeared to feature limited details on an
undisclosed flaw related to the Session Initiation Protocol
(SIP) in the networking giant's PIX series of firewalls and
security appliances.
SearchSecurity.com learned that the information Scholz shared
during his presentation involved the use of a proxy server to ring
multiple phones simultaneously in conjunction with SIP "fixup"
command. Essentially it pokes a hole through a PIX firewall to
allow SIP data to pass through and potentially allows for the
spoofing of a source device, in this case a telephony handset.
Scholz was working with Cisco and the US Computer Emergency
Readiness Team (US-CERT) on the matter, and was giving the
networking giant time to address any outstanding vulnerabilities
before disclosing more details.
So far Cisco has been unable to confirm the flaw exists.
"We've been working with Mr Scholz ever since his disclosure in
order to recreate this vulnerability," Cisco spokesman John Noh
said in an e-mail. "So far, we have not been able to reproduce the
issue and therefore cannot confirm his claim."
Nevertheless, he said Cisco will keep testing and will issue a
new security advisory as new information becomes available.
Information Security magazine editor-in-chief Michael Mimoso
contributed to this report.
This article originally appeared on
SearchSecurity.com.