Jump to content

Crypto breakthrough shows Flame was designed by world-class scientists


ShyWriter
 Share

Recommended Posts

.

screenhunter03jun081141.jpg

Crypto breakthrough shows Flame was designed by world-class scientists

The spy malware achieved an attack unlike any cryptographers have seen before.

by Dan Goodin - Jun 7, 2012 6:20 pm UTC

collision_attack_overview.png

An overview of a chosen-prefix collision

The Flame espionage malware that infected computers in Iran achieved mathematic breakthroughs that could only have been accomplished by world-class cryptographers, two of the world's foremost cryptography experts said

"We have confirmed that Flame uses a yet unknown MD5 chosen-prefix collision attack," Marc Stevens and B.M.M. de Weger wrote in an e-mail posted to a cryptography discussion group earlier this week. "The collision attack itself is very interesting from a scientific viewpoint, and there are already some practical implications."

"Collision" attacks, in which two different sources of plaintext generate identical cryptographic hashes, have long been theorized. But it wasn't until late 2008 that a team of researchers made one truly practical. By using a bank of 200 PlayStation 3 consoles to find collisions in the MD5 algorithm—and exploiting weaknesses in the way secure sockets layer certificates were issued—they constructed a rogue certificate authority that was trusted by all major browsers and operating systems. Stevens, from the Centrum Wiskunde & Informatica in Amsterdam, and de Weger, of the Technische Universiteit Eindhoven were two of the driving forces behind the research that made it possible.

Flame is the first known example of an MD5 collision attack being used maliciously in a real-world environment. It wielded the esoteric technique to digitally sign malicious code with a fraudulent certificate that appeared to originate with Microsoft. By deploying fake servers on networks that hosted machines already infected by Flame—and using the certificates to sign Flame modules—the malware was able to hijack the Windows Update mechanism Microsoft uses to distribute patches to hundreds of millions of customers.

According to Stevens and de Weger, the collision attack was unlike any that cryptographers have seen before. They arrived at that conclusion after using a custom-designed forensic tool to analyze Flame components.

"More interestingly, the results have shown that not our published chosen-prefix collision attack was used, but an entirely new and unknown variant," Stevens wrote in a statement distributed on Thursday. "This has led to our conclusion that the design of Flame is partly based on world-class cryptanalysis. Further research will be conducted to reconstruct the entire chosen-prefix collision attack devised for Flame."

The analysis reinforces theories that researchers from Kaspersky Lab, CrySyS Lab, and Symantec published almost two weeks ago. Namely, Flame could only have been developed with the backing of a wealthy nation-state. Stevens' and de Weger's conclusion means that, in addition to a team of engineers who developed a global malware platform that escaped detection for at least two years, Flame also required world-class cryptographers who have broken new ground in their field.

"It's not a garden-variety collision attack, or just an implementation of previous MD5 collisions papers—which would be difficult enough," Matthew Green, a professor specializing in cryptography in the computer science department at Johns Hopkins University, told Ars. "There were mathematicians doing new science to make Flame work."

SOURCE: http://arstechnica.c...to-breakthrough

Steve

Link to post
Share on other sites

Guest mrfreeman

Maybe we can finally let go of md5 now, it needs to be decommissioned in those areas where security is favoured.

There is one thing I don't understand though, the ars article mentions it is an entirely new collision method, the Microsoft however says:

"The attacker can then apply the collision algorithm documented by Sotirov..." (in 2008)

I see a little contradiction there.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
Back to top
×
×
  • Create New...

Important Information

This site uses cookies - We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.