[ISN] Hacker writes rootkit for Cisco's routers

From: InfoSec News (alerts@private)
Date: Thu May 15 2008 - 00:52:54 PDT


By Robert McMillan
IDG News Service
May 14, 2008

A security researcher has developed malicious rootkit software for Cisco 
Systems' routers, a development that has placed increasing scrutiny on 
the routers that carry the majority of the Internet's traffic.

Sebastian Muniz, a researcher with Core Security Technologies, developed 
the software, which he will unveil on May 22 at the EuSecWest conference 
in London.

Rootkits are stealthy programs that cover up their tracks on a computer, 
making them extremely hard to detect. To date, the vast majority of 
rootkits have been written for the Windows operating system, but this 
will mark the first time that someone has discussed a rootkit written 
for IOS, the Internetwork Operating System used by Cisco's routers. "An 
IOS rootkit is able to perform the tasks that any other rootkit would do 
on desktop computer operating systems," Muniz said in an interview.

Rootkits are typically used to install key-logging software as well as 
programs that allow attackers to remotely connect with the infected 
system. However, the most notorious rootkit of all, distributed by Sony 
BMG Music, stopped unauthorized CD copying.

A Cisco rootkit is particularly worrisome because, like Microsoft's 
Windows, Cisco's routers are very widely used. Cisco owned nearly 
two-thirds of the router market in the fourth quarter of 2007, according 
to research firm IDC.

In the past, researchers have built malicious software, known as "IOS 
patching shellcode," that could compromise a Cisco router, but those 
programs are custom-written to work with one specific version of IOS.

Muniz's rootkit will be different. "It could work on several different 
versions of IOS," he said.

The software cannot be used to break into a Cisco router -- an attacker 
would need to have some kind of attack code, or an administrative 
password on the router to install the rootkit, but once installed it can 
be used to silently monitor and control the device.

The rootkit runs in the router's flash memory, which contains the first 
commands that it uses to boot up, said EuSecWest conference organizer 
Dragos Ruiu.

Muniz said he has no plans to release the source code for his rootkit, 
but he wants to explain how he built it to counter the widespread 
perception that Cisco routers are somehow immune to this type of 
malware. "I've done this with the purpose of showing that IOS rootkits 
are real, and that appropriate security measures must be taken," he 

Security researcher Mike Lynn offered a similar rationalization for his 
controversial 2005 Black Hack presentation showing how to hack into a 
Cisco router and run a small "shellcode" program.

Lynn's presentation was "very shocking because, until then, nobody 
thought you could actually build exploits for Cisco," Ruiu said. "This 
rootkit is the next step."

Within hours of his 2005 Black Hat talk, Lynn was sued by Cisco, which 
claimed he had exposed trade secrets in violation of his Cisco end-user 
license agreement.

Cisco's suit was quickly settled, but Muniz and his employer clearly 
have Lynn's experience in mind as they ready for next week's conference. 
They declined to provide technical details on the presentation ahead of 
time. "We're still in the process of putting the whole presentation 
together, and we also need to work with Cisco before we talk to 
anybody," a Core spokesman said. "The big concern is making sure that 
everything is cool with Cisco."

Cisco declined to comment for this story.

Jennifer Granick, the Electronic Freedom Foundation lawyer who 
represented Lynn in 2005, said that Cisco could bring these trade-secret 
claims against Muniz, but because the technical community reacted so 
negatively to the 2005 lawsuit, she believes that this may not happen. 
"Cisco thinks of itself as really researcher-friendly," she said. "I 
think they will be very careful before filing legal action."

Still, the rootkit comes at a sensitive time for Cisco. Last week, the 
New York Times reported that the FBI considers the problem of fake Cisco 
gear a critical U.S. infrastructure threat.

In late February the FBI culminated a two-year investigation by breaking 
up a counterfeit Cisco distribution network and seizing an estimated 
$3.5 million worth of components manufactured in China. According to an 
FBI presentation on Operation Cisco Raider, fake Cisco routers, switches 
and cards were sold to the U.S. Navy, the U.S. Marine Corps., the U.S. 
Air Force, the U.S. Federal Aviation Administration, and even the FBI 

The U.S. Department of Defense has expressed concerns that the lack of 
security in the microelectronics supply chain could threaten the 
country's defense systems, and the idea that an attacker could sneak a 
rootkit onto a counterfeit Cisco system has security experts worried.

Cisco routers are typically compromised by hackers who are able to guess 
their administrative passwords, said Johannes Ullrich, chief research 
officer with the SANS Institute. But there are few tools around to check 
these systems for signs of hacking. "How would you find out?" he said. 
"That's the big problem."

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