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The Qakbot Botnet is Becoming More Advanced and Dangerous, Sophos Research Shows
[March 10, 2022]

The Qakbot Botnet is Becoming More Advanced and Dangerous, Sophos Research Shows


OXFORD, United Kingdom, March 10, 2022 (GLOBE NEWSWIRE) -- Sophos, a global leader in next-generation cybersecurity, today published a technical deep dive into Qakbot, explaining how the botnet is a becoming more advanced and dangerous to organizations. In a new article, “Qakbot Injects Itself into the Middle of Your Conversations,” Sophos researchers detail a recent Qakbot campaign that shows how the botnet spreads through email thread hijacking and collects a wide range of profile information from newly infected machines, including all the configured user accounts and permissions, installed software, running services, and more. The botnet then downloads a series of additional malicious modules that enhance the functionality of the core botnet, according to Sophos.

Qakbot’s malware code features unconventional encryption, which it also uses to conceal the content of its communications. Sophos decrypted the malicious modules and decoded the botnet’s command and control system to interpret how Qakbot receives instructions.

“Qakbot is a modular, multi-purpose botnet spread by email that has become increasingly popular with attackers as a malware delivery network, like Trickbot and Emotet,” said Andrew Brandt, principal threat researcher at Sophos. “Sophos’ deep analysis of Qakbot reveals the capture of detailed victim profile data, the botnet’s ability to process complex sequences of commands, and a series of payloads to extend the functionality of the core botnet engine. The days of thinking of ‘commodity’ bots as merely annoying are long gone.

“Security teams need to take seriously the presence of Qakbot infections on their network and investigate and remove every trace. Botnet infections are a known precursor for a ransomware attack. This is not simply because botnets can deliver ransomware, but because botnet developers sell or lease their access to breached networks. For example, Sophos has encountered Qakbot samples that deliver Cobalt Strike beacons directly to an infected host. Once the Qakbot operators have used the infected computer they can transfer, lease out or sell access to these beacons to paying customers.”

The Qakbot Infection Chain and Payloads

In the campaign Sophos analyzed, the Qakbot botnet inserted malicious messages into existing email conversations. The inserted emails include a short sentence and a link to download a zip file containing a malicious Excel spreadsheet. The user was asked to “enable content” to activate the infection chain. Oncethe botnet had infected a new target it performed a detailed profile scan, sharing the data with its command-and-control server and then downloading additional malicious modules.



The Qakbot botnet downloaded at least three different malicious payloads in the form of dynamic link libraries (DLL). According to Sophos, these DLL payloads provide the botnet with a wider range of capabilities.

The payloads were injected into browsers and contained the following:


  • A module that injects password-stealing code into webpages
  • A module that performs network scans, collecting data about other machines in proximity to the infected computer
  • A module that identified the addresses of a dozen SMTP (Simple Mail Transfer Protocol) email servers and then tried to connect to each one and send spam

Sophos Security Advice

Sophos recommends that users approach unusual or unexpected emails with caution, even when the messages appear to be replies to existing email threads. In the Qakbot campaign investigated by Sophos, a potential red flag for recipients was the use of Latin phrases in URLs.

Security teams should check that the behavioral protections provided by their security technologies prevent Qakbot infections from taking hold. Network devices will also alert administrators if an infected user attempts to connect to a known command-and-control address or domain.

Sophos endpoint products, such as Intercept X, protect users by detecting the actions and behaviors of attackers.

For further information read “Qakbot Injects Itself into the Middle of Your Conversations” on SophosLabs Uncut.

Additional Resources

  • Further details on the evolving cyberthreat landscape can be found in the Sophos 2022 Threat Report
  • Tactics, techniques, and procedures (TTPs) and more for different types of threats are available on SophosLabs Uncut, which provides Sophos’ latest threat intelligence
  • Information on attacker behaviors, incident reports and advice for security operations professionals is available on Sophos News SecOps
  • Learn more about Sophos’ Rapid Response Service that contains, neutralizes and investigates attacks 24/7
  • The four top tips for responding to a security incident  from Sophos Rapid Response and the Managed Threat Response Team
  • Read the latest security news and views on Sophos’ award-winning news website Naked Security and on Sophos News 

About Sophos
Sophos is a worldwide leader in next-generation cybersecurity, protecting more than 500,000 organizations and millions of consumers in more than 150 countries from today’s most advanced cyberthreats. Powered by threat intelligence, AI and machine learning from SophosLabs and SophosAI, Sophos delivers a broad portfolio of advanced products and services to secure users, networks and endpoints against ransomware, malware, exploits, phishing and the wide range of other cyberattacks. Sophos provides a single integrated cloud-based management console, Sophos Central – the centerpiece of an adaptive cybersecurity ecosystem that features a centralized data lake that leverages a rich set of open APIs available to customers, partners, developers, and other cybersecurity vendors. Sophos sells its products and services through reseller partners and managed service providers (MSPs) worldwide. Sophos is headquartered in Oxford, U.K. More information is available at www.sophos.com.


Contact: Samantha Powers, [email protected]

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