The Botnet Makes Detailed Profile Scans of Infected Computers, Downloads Additional Modules and Features Elaborate Encryption

OXFORD, U.K. — 三月 10, 2022 —

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. Once the 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.

关于 Sophos

Sophos 是全球领先的先进安全解决方案提供商和创新者,全面安全解决方案涵盖托管式侦测与响应 (MDR) 和事件响应服务,以及广泛的端点、网络、电子邮件和云安全技术。作为最大的纯网络安全厂商之一,Sophos 为全球超过 600,000 家企业和超过 1 亿用户提供防御主动攻击对手、勒索软件、网络钓鱼、恶意软件等威胁的保护。Sophos 的服务和产品通过 Sophos Central 管理控制台连接,并得到公司内部的跨领域威胁情报部门 Sophos X-Ops 的支持。Sophos X-Ops 情报优化整个 Sophos Adaptive Cybersecurity Ecosystem 自适应网络安全生态体系,包括一个中央数据湖,为客户、合作伙伴、开发人员和其他网络安全与信息技术供应商提供一组丰富的开放 API。Sophos为需要完全托管的安全解决方案的组织提供网络安全即服务。客户还可以直接利用 Sophos 的安全运行平台管理其网络安全,或者采用混合方法,为内部团队补充 Sophos 服务(包括威胁追踪与修复)。Sophos 通过世界各地的经销商合作伙伴和托管服务供应商 (MSP) 销售。Sophos 总部位于英国牛津。如欲了解更多信息,请访问 www.sophos.com