Rewterz Threat Alert – GuLoader Malspam Campaign – 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.

Impact

• Malware installation
• detection evation
• Information theft

Indicators of Compromise

MD5

• 825d982946af01bdd5be97b932330e76
• 21a7e2b29f07905c7436339bf8fd4c99
• 59a1161fe436923764b751a8d606d7c4

SHA-256

• 0ced498c384796edc59de60bdbd2c76c699fc29577ca21cdda9ace6a15e7b550
• 5b44d377e2ac43e289acf6f2ce0c3062955c523886c79f4235317535a563ec9c
• df06ee14dcd8d18eae4a818033bd9c3a2971adcf7c0fe9a2ee563a95e975286f

SHA-1

• ffe0a72f6a16d3eedbbda97d4a753e1c3ec50a55
• b29547cb597c93b38e9bfc003f8589a15cc032ea
• 862aedc2a4497f613a173d45fc2f585521e4b069

Remediation

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