Feeds

Stuxnet worm can reinfect PCs even after disinfection

Beware of poisoned Step7 files

High performance access to file storage

A security researcher has found yet another way the Stuxnet worm infiltrates computers used in nuclear plants and other industrial facilities, a technique that has the ability to reinfect machines even after they've been cleaned of the malware.

Stuxnet has already proven itself as one of the most sophisticated pieces of known malware ever. Its ability to target four vulnerabilities that until recently were unknown and unpatched allowed it to spread through USB sticks, Windows file shares, and other vectors. The worm is especially adept at targeting industrial-control applications developed by German software maker Siemens, allowing it to act as a guided missile of sorts that sabotages plants that meet very specific criteria.

Now, a researcher from anti-virus provider Symantec has discovered that Stuxnet also spreads by targeting files that administrators use to configure Siemens software. If present on a targeted Windows PC, the so-called Step7 files are automatically poisoned as soon as it is infected, Symantec's Nicolas Falliere wrote on Monday. When the files are opened later, they touch off a new round of infections.

“Stuxnet's ability to infect project files and run when they are opened is yet another propagation vector to add to the list,” Falliere said. “While we advise operators and programmers to be wary of project files from untrusted sources — internet forums, for instance — the most likely source of infection is likely to be a trusted party whose systems have been compromised by the threat.”

The technique can be especially effective in environments where Step7 files are located on a central computer and then copied to and executed on other machines. If Stuxnet is able to take hold of that central server, it can then infect local machines that are downstream from it.

Falliere also warned that the technique potentially allows Stuxnet to come back from the dead.

“Infected projects restored from backups may reintroduce the infection to previously cleaned machines so administrators should exercise caution when restoring files in this manner.”

His report is here. ®

High performance access to file storage

More from The Register

next story
Obama allows NSA to exploit 0-days: report
If the spooks say they need it, they get it
Parent gabfest Mumsnet hit by SSL bug: My heart bleeds, grins hacker
Natter-board tells middle-class Britain to purée its passwords
Web data BLEEDOUT: Users to feel the pain as Heartbleed bug revealed
Vendors and ISPs have work to do updating firmware - if it's possible to fix this
OpenSSL Heartbleed: Bloody nose for open-source bleeding hearts
Bloke behind the cockup says not enough people are helping crucial crypto project
One year on: diplomatic fail as Chinese APT gangs get back to work
Mandiant says past 12 months shows Beijing won't call off its hackers
Call of Duty 'fragged using OpenSSL's Heartbleed exploit'
So it begins ... or maybe not, says one analyst
German space centre endures cyber attack
Chinese code retrieved but NSA hack not ruled out
Experian subsidiary faces MEGA-PROBE for 'selling consumer data to fraudster'
US attorneys general roll up sleeves, snap on gloves
prev story

Whitepapers

Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
HP ArcSight ESM solution helps Finansbank
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.