Cisco's software will come under scrutiny a second time at this year's Black Hat hackers conference in Las Vegas starting next week.

Last year, the event was mired in controversy when the networking giant sued the conference organisers after security researcher Michael Lynn demonstrated a method for running unauthorised code on a Cisco router.

The lawsuit was settled after the organisers promised not to disseminate information on Lynn's research.

This year's conference organisers have warned that 15 new exploits will be discussed and two of them target NAC (Network Admission Control) and VoIP vulnerabilities, that affect products from a number of vendors, including Cisco.

However, it is unlikely that Cisco will be suing the conference this year, given that neither of the exploits target Cisco specifically.

Instead they relate to underlying technologies. One researcher, Ofir Arkin, the chief technology officer of Insightix will be speaking about NAC technologies "and ways to bypass them."

A second presentation, given by researchers at 3Com and SecureLogix will examine SIP (Session Initiation Protocol) used by VoIP systems.

"In it, we describe and demonstrate many real-world VoIP exploitation scenarios against SIP-based systems (Cisco, Avaya, Asterisk, etc)," the presenters wrote in a description of their talk.

Researchers will disclose three exploits that take advantage of bugs in the Linux-based Asterisk PBX telephony software.

And wireless security researchers David Maynor and Jon Ellch plan to show a way of running unauthorised software on a laptop computer by manipulating buggy code in the system's wireless device driver.

The man behind last year's troubles, Michael Lynn, will not be speaking at the event but the organisers credited him with inspiring new research work in the area of embedded devices, which will be one of the hottest areas of research at this year's conference.

By showing how Cisco's routers could be hacked and made to run unauthorised code just like a PC, Lynn helped change the way researchers think about many of these devices.

"Once he did that, it really opened people's eyes," said Black Hat director Jeff Moss. "The amount of people who are now beating up on embedded devices has changed. Now the floodgates are open."