Feeds

Storm worm smackdown as researchers unpick control system

But legal fears may kibosh clean-up

The Essential Guide to IT Transformation

A team of security researchers have developed a technique for automatically purging the remnants of the Storm worm infection from the internet. But the approach - which involves turning the botnet's command and control system against itself - could run foul of computer hacking laws in Germany and elsewhere, which ban the modification of computer systems without consent.

Nonetheless, the work of the team from Bonn University and RWTH Aachen University have advanced knowledge about how botnets (networks of compromised zombie PCs) are established and maintained that could advance the development of more acceptable tracking and take-down techniques.

The analysis of the infamous Storm worm botnet by Georg Wicherski, Tillmann Werner, Felix Leder, and Mark Schlösser established that the network of compromised machines established by the Storm worm is far less resilient than previously suspected, Heise Security reports.

PCs compromised by Trojan agents associated with the Storm worm turned compromised machines into zombie drones under the control of hackers. These hackers (or bot-herders) issue commands to compromised machines through control servers. If connection with a control server can't be established, then zombie clients use P2P techniques to locate other control servers.

Agents spreading the Storm worm first appeared two years ago, posing as information on the storms ravaging Europe at the time. In the months that followed, infectious agents adopted a variety of guises, such as greetings cards.

Microsoft's Malicious Software Removal Tool made big inroads into cleaning up infected systems. The steady stream of new email baits designed to recruit fresh marks into the Storm Worm botnet has dried up of late, another factor that means the number of clients in the Storm Worm networks has shrunk to a fraction of its previous high.

Despite this, as many as 100,000 compromised clients are thought to remain infected, way down on the millions infected by the Storm worm as its peak but still a scourge to internet hygiene.

The German researchers reckon that the Storm worm could have been dismantled at a far earlier stage. Instead of taking a black box approach of analysing the behaviour of compromised clients, the German academics took the Storm worm apart byte by byte - analysing the zombie client programs to work out what made it tick. The researchers paid particularly close attention to how compromised clients communicated with zombie control servers.

The boffins then developed their own client, capable of hooking into the Storm worm network, discovering in the process that servers have are not required to authenticate themselves to compromised clients. They also discovered that their eavesdropping client was treated as a trusted participant in the network, trusted to relay queries and command instructions.

These two factors made it possible for the researchers to divert compromised drones to dummy servers, under their control, from where infected machines might be instructed to download clean-up agents. The security researchers wrote a clean-up utility - delicately called Stormfucker - but never sent it into play because of concerns the action might be illegal or, more to the point, prompt lawsuits in the event something went wrong with the clean-up process.

The boffins also developed techniques to distribute the clean-up process so that it might be able to handle large loads and would be better at withstanding attempts to force it off the net by hackers. ®

Build a business case: developing custom apps

More from The Register

next story
14 antivirus apps found to have security problems
Vendors just don't care, says researcher, after finding basic boo-boos in security software
'Things' on the Internet-of-things have 25 vulnerabilities apiece
Leaking sprinklers, overheated thermostats and picked locks all online
iWallet: No BONKING PLEASE, we're Apple
BLE-ding iPhones, not NFC bonkers, will drive trend - marketeers
Multipath TCP speeds up the internet so much that security breaks
Black Hat research says proposed protocol will bork network probes, flummox firewalls
Only '3% of web servers in top corps' fully fixed after Heartbleed snafu
Just slapping a patched OpenSSL on a machine ain't going to cut it, we're told
Microsoft's Euro cloud darkens: US FEDS can dig into foreign servers
They're not emails, they're business records, says court
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Israel's Iron Dome missile tech stolen by Chinese hackers
Corporate raiders Comment Crew fingered for attacks
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.