Nachi worm infected Diebold ATMs

[InfoSec News <isn () c4i org>]

http://www.theregister.co.uk/content/55/34175.html

By Kevin Poulsen
SecurityFocus
Posted: 25/11/2003 

The Nachi worm compromised Windows-based automated teller machines at 
two financial institutions last August, according to ATM-maker 
Diebold, in the first confirmed case of malicious code penetrating 
cash machines. 

The machines were in an advanced line of Diebold ATMs built atop 
Windows XP Embedded, which, like most versions of Windows, was 
vulnerable to the RPC DCOM security bug exploited by Nachi, and its 
more famous forebear, Blaster. 

At both affected institutions the ATMs began aggressively scanning for 
other vulnerable machines, generating anomalous waves of network 
traffic that tripped the banks' intrusion detection systems, resulting 
in the infected machines being automatically cut off, Diebold 
executives said. 

"The outbound traffic from the ATM was stopped -- limited, from a 
network standpoint -- and effectively isolated," said Nick Billett, 
Diebold's director of software engineering. "In many cases, the 
machines were cleaned up that day." 

A patch for the critical RPC DCOM hole had been available from 
Microsoft for over a month at the time of the attack, but Diebold had 
neglected to install it in the infected machines. Billett defended the 
company's patching process, which he said involves testing each new 
bug fix, and deploying at a wide variety of institutions with a mix of 
network architectures. "A lot of those machines actually have to be 
visited by a service technician" to be patched, said Billett. "Our 
experience in the past is we are able to turn those around in one or 
two days." 

In this case, the two affected financial institutions, which Diebold 
declined to name, somehow slipped thought the cracks, said Billett. 
The company would not say how many machines were knocked out by the 
worm. 

Windows Bugs 

The incident highlights new dangers for financial institutions, as 
legacy ATMs running OS/2 and propriety communications protocols give 
way to more versatile and cost effective terminals built on Microsoft 
Windows and TCP/IP -- with all the attendant security problems. 

Though ATMs typically sit on private networks or VPNs, the most 
serious worms in the last year have demonstrated that 
supposedly-isolated networks often have undocumented connections to 
the Internet, or can fall to a piece of malicious code inadvertently 
carried beyond the firewall on a laptop computer. 

January's Slammer worm indirectly shut down some 13,000 Bank of 
America ATMs by infecting database servers on the same network, and 
spewing so much traffic that the cash machines couldn't processes 
customer transactions. 

"I think of ATMs as a relative of SCADA systems, as those things not 
really being on the Internet, but being on some network," says Peter 
Lindstrom, an analyst with Spire Security. "In some ways, it's kind of 
ironic, that I think standardization across the board has created some 
of the issues." 

In response to the problem, and to meet their customer's IT 
requirements, Diebold next month plans to begin shipping all new 
Windows-based ATMs preinstalled with a software-based firewall, made 
by Sygate Technologies. The company will also offer to put the Sygate 
product on existing machines already in the field. "We have many 
customers that are placing ATMs on their network, and as a result of 
that we have to meet certain criteria ... we haven't had to meet 
before," said Chuck Somers, vice president of global software 
development at Diebold. 

Somers said he wasn't aware of Diebold ATMs being infected by earlier 
Windows worms, like Blaster or Slammer. "I'm not aware specifically of 
machines that were [comprised] as a result of previous ones," he said. 
"I was made aware specifically of the ones with Nachi, and that was 
cleaned up" 

Microsoft had no immediate comment Monday. 

Despite the allure of hard cash, don't expect to see a rash of 
made-for-Hollywood ATM hacks -- machines around the country suddenly 
spitting out wads of 20s at random, said Marc Maiffret, Windows expert 
and "chief hacking officer" at California-based eEye Digital Security. 

"The actual point of service terminal itself getting infected-- that's 
pretty crazy," said Maiffret. "But worms are always going to be able 
to infect a lot more interesting machines than individual intruders 
are." Moreover, before reaching an ATM network, a human attacker would 
likely encounter more alluring high-finance targets along the way. 
"They're going to have to go through a lot of juicer networks first." 



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