Stealthy malware 'Poweliks' resides only in system registry

The malware is persistent across system reboots, despite not having any files on disk

A new malware program called Poweliks attempts to evade detection and analysis by running entirely from the system registry without creating files on disk, security researchers warn.

The concept of "fileless" malware that only exists in the system's memory is not new, but such threats are rare because they typically don't survive across system reboots, when the memory is cleared. That's not the case for Poweliks, which takes a rather new approach to achieve persistence while remaining fileless, according to malware researchers from G Data Software.

When it infects a system, Poweliks creates a startup registry entry that executes the legitimate rundll32.exe Windows file followed by some encoded JavaScript code. This triggers a process similar in concept to a Matryoshka Russian nesting doll, said Paul Rascagnères, senior threat researcher at G Data, in a blog post.

The JavaScript code checks whether Windows PowerShell, a command-line shell and scripting environment, is present on the system. If it isn't, it downloads and installs it and then it decodes some more code that is actually a PowerShell script.

The PowerShell script is executed by using a trick to bypass a default protection in Windows that prevents the launch of unknown PowerShell scripts without user confirmation, Rascagnères said. The script then decodes and executes shellcode which injects a DLL (dynamic link library) directly into the system memory.

Once it is running in memory, the rogue DLL component connects to two IP (Internet Protocol) addresses in Kazakhstan to receive commands. It can be used to download and install other threats, depending on the attacker's needs and intentions.

During the entire process, from executing the JavaScript code to the final DLL injection, the malware does not create any malicious files on the hard disk drive, making it difficult for antivirus programs to detect it.

Furthermore, the name of the startup registry key created by Poweliks is a non-ASCII character. This is a trick that prevents regedit -- the Windows registry editor tool -- and possibly other programs from displaying the rogue start-up entry, making it difficult for both users and malware analysts to manually spot the infection.

Some Poweliks variants have been distributed through malicious Microsoft Word documents attached to spam emails that purported to come from Canada Post or USPS. The malicious documents exploited a remote code execution vulnerability in Microsoft Office 2003, 2007 and 2010 that was patched by Microsoft in April 2012. However, according to other reports, the malware is also distributed through drive-by download attacks that use Web exploits.

To block malware like Poweliks, "antivirus solutions have to either catch the file (the initial Word document) before it is executed (if there is one), preferably before it reached the customer's email inbox," Rascagnères said. "Or, as a next line of defense, they need to detect the software exploit after the file's execution, or, as a last step, in-registry surveillance has to detect unusual behavior, block the corresponding processes and alert the user."

Security researchers from Trend Micro, who have also analyzed the threat, believe that other malware creators may adopt the techniques used by Poweliks in the future.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags trend microsecurityDesktop securityExploits / vulnerabilitiesG Data Softwaremalwareantivirus

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Lucian Constantin

IDG News Service
Show Comments

Cool Tech

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Breitling Superocean Heritage Chronographe 44

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

David Coyle

Brother PocketJet PJ-773 A4 Portable Thermal Printer

I rate the printer as a 5 out of 5 stars as it has been able to fit seamlessly into my busy and mobile lifestyle.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?