“Shai-Hulud” Self-Replicating Malware — Threat Analysis Report CyberDudeBivash Authority Report

 

Executive Summary

• Threat name: Shai-Hulud — a newly identified self-replicating malware family.

• Category: Worm / self-propagating malware with hybrid traits (worm + ransomware).

• Propagation: Exploits network misconfigs, lateral movement via SMB/RDP/SSH, plus malicious document/email vectors.

• Risks: Rapid spread across enterprise networks, privilege escalation, potential data destruction/encryption.

• Notable trait: Payload re-seeds itself persistently, even after partial clean-up.

• Action now: Segment networks, apply strict credential hygiene, implement EDR policies for worm heuristics, patch exposed services, and prepare incident response playbooks.

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Technical Overview

• Infection vector: phishing attachments, malicious macros, weaponized PDF/Office docs.

• Self-replication:

  • Scans subnets for open ports (445/3389/22).

  • Brute-forces weak creds and re-deploys binary.

  • Creates scheduled tasks / systemd services for persistence.

• Payload actions:

  • Keylogging + credential harvesting.

  • Optional ransomware module encrypts critical files.

  • Backdoor channel via HTTP(S) or DNS tunneling.

• Resilience: kills AV/EDR processes, mutates file hashes, re-seeds itself from infected peers.

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MITRE ATT&CK Mapping

• Initial Access: Phishing (T1566), Exploit Public-Facing Application (T1190).

• Execution: User Execution (T1204), Command-Line Interface (T1059).

• Persistence: Scheduled Task/Job (T1053), Systemd Service (Linux).

• Privilege Escalation: Exploitation for Privilege Escalation (T1068).

• Lateral Movement: SMB/Windows Admin Shares (T1021.002), SSH (T1021.004).

• Impact: Data Encrypted for Impact (T1486).

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Indicators of Compromise (IoCs)

Files/Hashes (samples):

• shaihulud.dll

• wormloader.exe

• /tmp/.shaihulud

Network:

• Outbound traffic to domains with “sandworm[.]” or “arrakis[.]” strings.

• Repeated DNS queries for TXT records (used for C2).

Behavioral:

• Rapid creation of scheduled tasks across multiple endpoints.

• Sudden spike in SMB/SSH login failures followed by successes.

• EDR/AV tamper attempts.

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Threat Hunting Playbook

Splunk Query — Detect abnormal SMB brute force

index=wineventlog EventCode=4625 OR EventCode=4624 
| stats count by src_ip, dest_host, user
| where count > 100 within 5 minutes

Elastic Detection Rule

event.dataset:"authentication" AND (event.outcome:"failure" OR event.outcome:"success")
AND service.name:"smb"

Sigma Rule (EDR Tampering)

title: Shai-Hulud Malware AV/EDR Tamper
logsource: windows
detection:
  selection:
    EventID: 7036
    ServiceName|contains:
      - "Defender"
      - "EDR"
  condition: selection
level: high

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Response & Containment

1. Isolate infected hosts immediately.

2. Block known IoCs at firewall/proxy.

3. Rotate credentials for compromised accounts.

4. Rebuild hosts (due to persistence).

5. Check backups (ensure clean restore points).

6. Communicate & escalate — legal, compliance, insurance.

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Long-Term Mitigation

• Network segmentation (stop worm propagation).

• MFA for remote access (VPN/RDP/SSH).

• Disable SMBv1; restrict RDP exposure.

• Continuous vulnerability patching.

• Endpoint hardening with behavioral EDR rules.

• Regular incident response exercises simulating worm outbreaks.

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