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Rewterz Threat Alert – Gootkit Trojan – Active IOCs
August 17, 2021
Rewterz Threat Alert – FormBook Malware – Active IOCs
August 17, 2021

Rewterz Threat Alert – GuLoader Malspam Campaign – Active IOCs

August 17, 2021

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 evasion
  • Information theft

Indicators of Compromise

MD5

  • 8056c1da01723959661caf103a001271
  • a999f70ef203107555ad230346b89c80
  • cef00aaa5b2889b6d9ae4d77298c9559

SHA-256

  • b05b832ba690f4fee5cb0c810f9a329592ef5736a01f77d2190d7d7d24fe9a0c
  • 63349f5e1cb7e662593709d14ed76838362d5b81fd3efedf1b7b307f343fe377
  • a3a5266a7acb1335d9e5a4afc026046ccdd824f6c484f3ae1d5d11030ccf65d8

SHA-1

  • 94b3b830fa2cdbef62306d497e90a381625b795b
  • 2eee21bb0c57c8542b7e0518b662a9a07f47c821
  • 09fe3291a0e0f76580874808be00694458297136

Remediation

  • Block the threat indicators at their respective controls.
  • Do not download files attached in untrusted emails.
  • Do not download files from untrusted sources on the internet.
  • Search for IOCs in your environment.
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      • Compromise Assessment
      • APT Assessment
      • Penetration Testing
      • Secure Architecture Design & Review
      • Red Team Assessment
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    • Respond
      • Incident Response
      • Incident Analysis
  • Transform
    • SOC Consultancy
    •     SOC Maturity Assessment
    •     SOC Model Evaluation
    •     SOC Gap Analysis
    •     SIEM Gap Analysis
    •     SIEM Optimization
    •     SOC Content Pack
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    • Tabletop Exercise
    • Simulated Cyber Attack Exercises
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      • Onsite SOC
      • Hybrid SOC
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      • Managed Risk-Based SOAR
      • Managed Penetration Testing
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