Rewterz Threat Alert – GuLoader Malspam Campaign spawns AgentTesla 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.

GuLoader malware spawns AgentTesla In its latest campaign. 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

MD5

• abca4f0519ba9deaf2bf316c1c1d10af

SHA-256

• 4ddb81c6aedc186cd322320116f6054670acb7bae1188bce26d034c5070ebe69

SHA-1

• 8b195cfa21fd2e2495947a2bb546fc9c7cd3748d

URL

http[:]//allvar[.]hr/WED4[.]psm

Remediation

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