AgentTesla Mass Distribution

On August 30 and 31, 2022, CERT-UA revealed a burst of adversary activity massively distributing phishing emails among Ukrainian, Austrian, and German organizations. According to the corresponding CERT-UA#5252 alert, hackers exploit the email attachment vector spreading the notorious AgentTesla info-stealing malware. The malicious activity can be attributed to the behavior patterns of the hacking collective tracked as UAC-0120.

AgentTesla Malware Distribution: Analysis of the Latest Email Campaigns by UAC-0120 

Since the world entered the global cyber war when russia launched its major invasion of Ukraine, russia-linked hacking collectives escalated their malicious activity by launching cyberespionage campaigns and destructive cyber-attacks. As part of those campaigns, adversaries leveraged info-stealing malware samples, like IcedID Trojan and AgentTesla spyware. The latter belongs to one of the widely-used spyware Trojans designed to steal sensitive data from compromised users. AgentTesla malware emerged in earlier cyber-attacks against Ukraine attributed to the malicious activity of the UAC-0041 hacking group

On August 31, 2022, CERT-UA issued an alert CERT-UA#5252 warning the global cyber defender community of a new wave of cyber-attacks by the UAC-0120 hacking group massively spreading AgentTesla spyware. Adversaries launch ongoing phishing email campaigns targeting organizations across Ukraine, Austria, and Germany. These emails contain malicious IMG attachments named “Technisches Zeichnen” (ā€œTechnical Drawingā€) used as phishing lures to trick victims into opening them and spreading infection. The IMG lure comes with a CHM file, which, if opened, executes malicious JavaScript code. The latter downloads and launches the node.txt file via PowerShell script. 

As a result, the PowerShell code executes DLL and EXE files, the latter being AgentTesla spyware, which infects the compromised systems. According to the CERT-UA research, similar phishing emails were delivered on August 11, but they used other lures for email subjects and attachments. 

Detecting the UAC-0120 Activity: Sigma Rules to Proactively Defend Against Phishing Attacks Spreading AgentTesla

To proactively defend against the emerging adversary activity of diverse hacking collectives spreading info-stealing malware, cybersecurity researchers are looking for ways to boost threat detection capabilities and accelerate threat hunting velocity. The SOC Prime Team curates a set of unique Sigma rules to detect the malicious activity of the UAC-0120 group, which is behind ongoing cyber-attacks distributing AgentTesla spyware. Since these phishing campaigns target multiple organizations from Ukraine, Austria, and Germany, cyber defenders should stay on alert to timely identify the infection in their organizationā€™s infrastructure and mitigate the potential threat. 

Cybersecurity practitioners can browse SOC Prime for the related threats based on the group identifier ā€œUAC-0120ā€ and instantly gain access to relevant Sigma rules enriched with insightful contextual metadata, like MITRE ATT&CKĀ® and CTI references:

Sigma rules to detect the malicious activity of the UAC-0120 group massively distributing AgentTesla malware

All Sigma rules are available in SOC Primeā€™s Detection as Code platform and can be applied across supported industry-leading SIEM, EDR, and XDR technologies. 

Instantly access context-enriched Sigma rules for AgentTesla malware detection directly from SOC Primeā€™s Cyber Threats Search Engine. Click the Explore Detections button and drill down to the relevant detection content accompanied by comprehensive contextual information for in-depth threat investigation. Need more than just detection rules? Gain from Detection as Code available on demand offering utmost flexibility with a pre-paid balance.

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MITRE ATT&CKĀ® Context

All dedicated Sigma rules are aligned with the MITRE ATT&CKĀ® framework addressing the following adversary tactics and techniques enabling cybersecurity professionals to instantly gain insights into the MITRE ATT&CK context behind the ongoing email campaigns of the UAC-0120 group:

Stay ahead of emerging threats with on-demand access to the latest and most relevant Detection-as-Code content available in SOC Primeā€™s platform. Choose the On-Demand subscription plan and save up to 2,200 hours on threat research and detection content development while maximizing the value of your SOC team resources.Ā 

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