Written by
Liam Tung, Contributor
Liam Tung
Contributor
Liam Tung is an Australian business technology journalist living a few too many Swedish miles north of Stockholm for his liking. He gained a bachelors degree in economics and arts (cultural studies) at Sydney’s Macquarie University, but hacked (without Norse or malicious code for that matter) his way into a career as an enterprise tech, security and telecommunications journalist with ZDNet Australia.
Full Bio
on December 10, 2021
| Topic: Security
Why hackers are targeting web servers with malware and how to protect yours
Watch Now
Qakbot, a top trojan for stealing bank credentials, has in the past year started delivering ransomware and this new business model is making it harder for network defenders to detect what is and isn’t a Qakbot attack.
Qakbot, is an especially versatile piece of malware, and has been around for over a decade and survived despite multi-year efforts by Microsoft and other security firms to stamp it out. Qakbot in 2017 adopted WannaCry’s lateral movement techniques, such as infecting all network shares and drives, brute forcing Active Directory accounts and using the SMB file-sharing protocol to create copies of itself.
Kaspersky’s recent analysis of Qakbot concluded that it won’t disappear anytime soon. Its detection statistics for Qakbot indicated it had infected 65% more PCs between January to July 2021 compared to the same period in the previous year. So, it is a growing threat.
SEE: Hackers are turning to this simple technique to install their malware on PCs
Microsoft highlights that Qakbot is modular, allowing it to appear as separate attacks on each device on a network, making it difficult for defenders and security tools to detect, prevent and remove. It’s also difficult for defenders to detect because Qakbot is used to distribute multiple variants of ransomware.
“Due to Qakbot’s high likelihood of transitioning to human-operated attack behaviors including data exfiltration, lateral movement, and ransomware by multiple actors, the detections seen after infection can vary widely,” the Microsoft 365 Defender Threat Intelligence Team say in its report.
Given these difficulties pinpointing a common Qakbot campaign, the Microsoft team has profiled the malware’s techniques and behaviors to help security analysts root out this versatile malware.
The primary delivery mechanism is emailed attachments, links, or embedded images. However, it’s also known to use Visual Basic for Applications (VBA) macros as well as legacy Excel 4.0 macros to infect machines. TrendMicro analyzed a large Qakbot campaign in July that used this technique.
Other groups like Trickbot recently started using Excel 4.0 macros to call Win32 APIs and run shell commands. As a result, Microsoft disabled these macro types by default, but Qakbot uses text in an Excel document to trick targets into manually enabling the macro.
Qakbot employs process injection to hide malicious processes, creating scheduled tasks to persist on a machine, and manipulating the Windows registry.
Once running on an infected device, it uses multiple techniques for lateral movement, employs the Cobalt Strike penetration-testing framework, or deploys ransomware.
The FBI last year warned that Qakbot trojans were delivering ProLock, a “human-operated ransomware” variant. It was a worrying development because computers infected with Qakbot on a network must be isolated because they’re a bridge for a ransomware attack.
Microsoft notes MSRA.exe and Mobsync.exe have been used by Qakbot for this process injection in order to run several network ‘discovery’ commands and then steal Windows credentials and browser data.
Qakbot’s Cobalt Strike module lends itself to other criminal gangs who can drop their own payloads, such as ransomware. Per Trend Micro, Qakbot has delivered MegaCortex and PwndLocker (2019), Egregor, and ProLock (2020), and Sodinokibi/REvil (2021).
“Qakbot has a Cobalt Strike module, and actors who purchase access to machines with prior Qakbot infections may also drop their own Cobalt Strike beacons and additional payloads,” Microsoft notes.
“Using Cobalt Strike lets attackers have full hands-on-keyboard access to the affected devices, enabling them to perform additional discovery, find high-value targets on the network, move laterally, and drop additional payloads, especially human-operated ransomware variants such as Conti and Egregor.”
Microsoft’s recommended mitigations to minimize Qakbot’s impact include enabling Office 365 phishing protection, enabling SmartScreen and network in the Edge browser, and ensuring runtime macro scanning by turning Windows Antimalware Scan Interface (AMSI) on.
AMSI is supported by Microsoft Defender antivirus and several third-party antivirus vendors. AMSI support for Excel 4.0 macros arrived in March, so it’s still a relatively new feature.
Security
Hackers are using new malware which hides between blocks of junk code
Crooks are selling access to hacked networks. Ransomware gangs are their biggest customers
Here’s the perfect gift to protect anyone with a computer
These researchers wanted to test cloud security. They were shocked by what they found
Hackers are turning to this simple technique to install their malware on PCs
Hit by ransomware? Don’t make this first obvious mistake
Security TV
|
Data Management
|
CXO
|
Data Centers