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, 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 evasion
• Information theft

Indicators of Compromise

MD5

• 2d43c9fc5eee0658f1ebdef9d2e4c184
• 6186f5b324b817103f8b2fe202221da2

SHA-256

• c5615a2ab19a2bcd8d33b5a721f04d09218103cfaa4005ee044fe3c583f09d68
• 1c0d93b0cf7a58a0cc6431c0aa5da4a88cbb9522c616006c30c747bd306da191
• 0a6cf16e375fcdee8d7bd236070a75418d777112f54d55b35876733aa579759f
• 5e41dbb4b4494c282396b7a327076ffb498978fc070b3ac7bc0cbcf57e2eba78

SHA1

• a3b96cd35708c5555363e365a1ab14f0de5f355c
• c70e70bb97405c71303694f265b53786d41b73b2

Remediation