Feeds

Gameover ZeuS adds nasty trick

Crypto to slip through firewalls

Providing a secure and efficient Helpdesk

The password-stealing ZeuS variant, Gameover, is now using encryption to get around perimeter security kit like firewalls and intrusion detection systems.

Malcovery's Gary Warner outlines the new behaviour of the malware at his blog, here, on the basis that the threat needed to be known beyond the circle of the company's customers.

Gameover ZeuS is a password-stealer, and has been spotted in attacks against Bitcoin users in China, and against CryptoLocker.

Warner writes that the .EXE file associated with Gameover ZeuS should by now be spotted by up-to-date security, so the malware's authors have begun encrypting the file and distributing it as a non-executable .ENC file.

Of course, a .ENC file isn't executable (which is why it could get a pass mark from security systems), so the authors have to find some way to decrypt it at the target. They do this via a file included in the phishing e-mail that kicks off an attack: “the .zip file attached to the email has a NEW version of UPATRE that first downloads the .enc file from the Internet and then DECRYPTS the file, placing it in a new location with a new filename, and then causing it both to execute and to be scheduled to execute in the future”, Warner writes.

Boldizsár Bencsáth, from CrySys Lab in Hungary, explains the encryption here. It's not terribly sophisticated (since the purpose isn't to hide sensitive data, but merely to present security systems with a file format they'll ignore): the file is compressed, then XORd with a 32-bit key. The e-mail dropper that infects victims simply reverses this process. ®

Choosing a cloud hosting partner with confidence

More from The Register

next story
SMASH the Bash bug! Apple and Red Hat scramble for patch batches
'Applying multiple security updates is extremely difficult'
Shellshock: 'Larger scale attack' on its way, warn securo-bods
Not just web servers under threat - though TENS of THOUSANDS have been hit
Apple's new iPhone 6 vulnerable to last year's TouchID fingerprint hack
But unsophisticated thieves need not attempt this trick
Hackers thrash Bash Shellshock bug: World races to cover hole
Update your gear now to avoid early attacks hitting the web
Oracle SHELLSHOCKER - data titan lists unpatchables
Database kingpin lists 32 products that can't be patched (yet) as GNU fixes second vuln
Who.is does the Harlem Shake
Blame it on LOLing XSS terroristas
Researchers tell black hats: 'YOU'RE SOOO PREDICTABLE'
Want to register that domain? We're way ahead of you.
Stunned by Shellshock Bash bug? Patch all you can – or be punished
UK data watchdog rolls up its sleeves, polishes truncheon
prev story

Whitepapers

A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.