Security researchers observed an Astaroth attack that used only living-off-the-land techniques to run the backdoor directly in memory on Windows machines.

The Microsoft Defender ATP Research Team detected the Astaroth attack after noticing an anomaly from a Windows Defender Antivirus algorithm used for catching fileless campaigns. This led the researchers to an infection chain that relied strictly on living-off-the-land techniques — the use of regular tools already present on the system — to avoid raising any red flags.

The infection chain began with a series of spear phishing emails that contained malicious links to redirect users to a LNK file. When double-clicked, the LNK file executed the Windows Management Instrumentation Command (WMIC) tool with the /Format parameter. The campaign then executed JavaScript code to download payloads using the Bitsadmin tool.

At this point, the attacks used Certutil to decode the payloads and then the Regsvr32 tool to run a series of dynamic link libraries (DLLs). This chain of events eventually led one DLL to load into Userinit and then load Astaroth as its final payload. With Astaroth activated, threat actors could use the backdoor to steal sensitive information and move laterally across the network.

Astaroth Abuses Windows Services and Legitimate Tools

Astaroth attacks often abuse legitimate Windows services. In September 2018, Cofense spotted a campaign that compromised 8,000 machines in one week by exploiting WMIC and Certutil. News of this attack came several months before Cybereason detected a campaign in which threat actors abused legitimate operating system functionality and security-related products to distribute the backdoor to users in Brazil.

Awareness Is the Best Defense Against an Astaroth Attack

Security awareness training to educate employees about phishing campaigns and other digital threats can help defend against an Astaroth attack. Analysts should use this education framework in tandem with a patch management strategy and a deep familiarity with built-in Windows code to spot anomalies that could be indicative of fileless attacks.

More from

Vulnerability resolution enhanced by integrations

2 min read - Why speed is of the essence in today's cybersecurity landscape? How are you quickly achieving vulnerability resolution?Identifying vulnerabilities should be part of the daily process within an organization. It's an important piece of maintaining an organization’s security posture. However, the complicated nature of modern technologies — and the pace of change — often make vulnerability management a challenging task.In the past, many organizations had to support manual integration work to get different security systems to ‘talk’ to each other. As…

How I got started: SIEM engineer

2 min read - As careers in cybersecurity become increasingly more specialized, Security Information and Event Management (SIEM) engineers are playing a more prominent role. These professionals are like forensic specialists but are also on the front lines protecting sensitive information from the relentless onslaught of cyber threats. SIEM engineers meticulously monitor, analyze and manage security events and incidents within an organization. They leverage SIEM tools to aggregate and correlate data, enabling them to detect anomalies, identify potential threats and respond swiftly to security…

Tequila OS 2.0: The first forensic Linux distribution in Latin America

3 min read - Incident response teams are stretched thin, and the threats are only intensifying. But new tools are helping bridge the gap for cybersecurity pros in Latin America.IBM Security X-Force Threat Intelligence Index 2023 found that 12% of the security incidents X-force responded to were in Latin America. In comparison, 31% were in the Asia-Pacific, followed by Europe with 28%, North America with 25% and the Middle East with 4%. In the Latin American region, Brazil had 67% of incidents that X-Force…

Cost of a data breach 2023: Geographical breakdowns

4 min read - Data breaches can occur anywhere in the world, but they are historically more common in specific countries. Typically, countries with high internet usage and digital services are more prone to data breaches. To that end, IBM’s Cost of a Data Breach Report 2023 looked at 553 organizations of various sizes across 16 countries and geographic regions, and 17 industries. In the report, the top five costs of a data breach by country or region (measured in USD millions) for 2023…