Rewterz Threat Alert – GuLoader Malspam Campaign Spawns Agent Tesla Malware – Active IOCs

Severity

Medium

Analysis Summary

Guloader is currently being distributed via spam email campaigns with archived attachments that contain the malware. The majority of malware downloaded by GuLoader is commodity malware, with AgentTesla, FormBook, and NanoCore being the most predominant. This downloader typically stores its encrypted payloads on Google Drive. It has also downloaded its payloads from Microsoft OneDrive and also from compromised or attacker-controlled websites. By utilizing legitimate file-sharing websites, GuLoader can evade network-based detection, as these services are not generally filtered or inspected in corporate environments. Usually, the downloaded payloads are encrypted with a hard-coded XOR key embedded in the malware, making it difficult for file-sharing service providers to identify the payload as malicious. This time, the GuLoader Shellcode injector is being distributed via a file named “EXTERNAL RFPPAN India Epoxy/PU 2021”. The scope of this campaign so far seems to be global.

Recently, GuLoader malware spawns AgentTesla In its latest campaign by fake invoice as malspam subject. AgentTesla is renowned for stealing data from a variety of target workstations’ apps, including browsers, FTP clients, and file downloaders.

Impact

• Malware installation
• detection evation
• Information theft

Indicators of Compromise

Domain Name

• ftp[.]acbcr[.]ro

Email

• info@acbcr[.]ro

MD5

• 993dbd881f2e6899dee678fd022e0544

SHA-256

• 73a826fb5c1546882857a571d22356369bcd3ff3a16c1bfb5ec8a3c0297ed266

SHA-1

• 27eae3bbf384e8df4221fbbdfd0111da90aa2d7e

Remediation

• Block the threat indicators at their respective controls.
• Search for IOCs in your environment.