Cisco: No zero-day at Black Hat

There was no new security vulnerability disclosed in Cisco Systems' PIX firewall at Black Hat, the networking giant said this week. It has investigated claims by a security researcher that the firewall was flawed, but could not reproduce the issue.

"(We're) closing the loop on this one...for now," Cisco spokesman John Noh wrote in an e-mail to CNET News.com.

In a presentation at the Black Hat security event in Las Vegas earlier this month, Hendrik Scholz of Germany's Freenet Cityline briefly mentioned a flaw in Cisco software. This apparent flaw had not been patched, he said.

"We've been working with Mr. Scholz ever since his disclosure in order to re-create this vulnerability," Noh wrote. "So far, we have not been able to reproduce issue and therefore cannot confirm his claim."

Cisco will keep testing and updating a security notice on the issue with new information if it becomes available, Noh said.

According to Scholz the PIX firewall in Cisco's PIX 500 Series Security Appliances could be compromised by sending a specially crafted SIP message to the appliance. SIP, or session initiation protocol, is used in VoIP (voice over Internet Protocol) applications.

Cisco did not know of the possible problem before Scholz's Black Hat presentation, the company said.

Cisco's reaction to the disclosure at Black Hat this year is noticeably different than last year when the networking giant drew the ire of many Black Hat and DefCon attendees after it sued a security researcher and conference organizers.