Feeds

Conficker variant dispenses with need to phone home

Stealth variant Sidesteps MS-led takedown effort

Top 5 reasons to deploy VMware with Tegile

Virus authors have released a new variant of the infamous Conficker (Downadup) worm with enhanced auto-update features.

The changes in the new strain of the malware, dubbed Conficker B++, make it possible for malware authors to push out new code without publishing it on pre-programmed sites, as with earlier variants. The earlier approach has been frustrated by the recent formation of an alliance led by Microsoft geared up to block and take down sites associated with the worm.

"Perhaps as one response to the cabal's action, or simply to produce a more efficient push-based updating service, the Conficker authors have released a variant of Conficker B, which significantly upgrades their ability to flash Conficker drones with Win32 binaries from any address on the Internet," explains an analysis by security firm SRI International.

Conficker B++ is somewhat similar to Conficker B, with 294 of 297 sub-routines the same and 39 additional subroutines. The latest variant, first spotted on 16 February, is even more sneaky than its previous incarnations, SRI explains.

Conficker B++ is no longer limited to reinfection by similarly structured Conficker DLLs, but can now push new self-contained Win32 applications. These executables can infiltrate the host using methods that are not detected by the latest anti-Conficker security applications.

The malware also creates an additional backdoor on compromise machines to create an altogether trickier infectious agent, SRI explains.

In Conficker A and B, there appeared only one method to submit Win32 binaries to the digital signature validation path, and ultimately to the CreateProcess API call. This path required the use of the Internet rendezvous point to download the binary through an HTTP transaction.

Under Conficker B++, two new paths to binary validation and execution have been introduced to Conficker drones, both of which bypass the use of Internet Rendezvous points: an extension to the netapi32.dll patch and the new named pipe backdoor. These changes suggest a desire by the Conficker's authors to move away from a reliance on Internet rendezvous points to support binary update, and toward a more direct flash approach.

SRI reckons that Conficker-A has infected 4.7m machines, at one time or another, while Conficker-B has hit 6.7m IP addresses. These figures, as with previous estimates, come from an analysis of the number of machines that have ever tried to call into malware update sites. The actual number of infected hosts at any one time is lower than that. SRI estimates the botnet controlled by Conficker-A and Conficker-B is around 1m and 3m hosts, respectively, or a third of the raw estimate.

SRI's detailed analysis of Conficker, which includes flow charts illustrating the viral and detailed technical analysis, can be found here. ®

Top 5 reasons to deploy VMware with Tegile

More from The Register

next story
UK smart meters arrive in 2020. Hackers have ALREADY found a flaw
Energy summit bods warned of free energy bonanza
DRUPAL-OPCALYPSE! Devs say best assume your CMS is owned
SQLi hole was hit hard, fast, and before most admins knew it needed patching
Knock Knock tool makes a joke of Mac AV
Yes, we know Macs 'don't get viruses', but when they do this code'll spot 'em
Feds seek potential 'second Snowden' gov doc leaker – report
Hang on, Ed wasn't here when we compiled THIS document
Mozilla releases geolocating WiFi sniffer for Android
As if the civilians who never change access point passwords will ever opt out of this one
Why weasel words might not work for Whisper
CEO suspends editor but privacy questions remain
prev story

Whitepapers

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.
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.
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?
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Mitigating web security risk with SSL certificates
Web-based systems are essential tools for running business processes and delivering services to customers.