ThreatFox: Hook IOCs

Hunt Hypothesis

This hunt targets the presence of specific IOCs linked to the Hook threat actor, indicating potential compromise or reconnaissance activity within the environment. Proactively hunting for these indicators allows the SOC to identify early-stage intrusions and mitigate the high-severity risks associated with this actor before they can establish persistence or exfiltrate data.

IOC Summary

Malware Family: Hook Total IOCs: 2 IOC Types: ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Hook
let malicious_ips = dynamic(["37.220.31.123", "31.77.12.106"]);
CommonSecurityLog
| where DestinationIP in (malicious_ips) or SourceIP in (malicious_ips)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, DeviceAction, Activity
| order by TimeGenerated desc

KQL: Ip Hunt Device

// Hunt in Defender for Endpoint network events
let malicious_ips = dynamic(["37.220.31.123", "31.77.12.106"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Hook

False Positive Guidance

• Scenario: A security operations team deploys a YARA rule or Sigma correlation logic that includes the specific Hook IOCs (e.g., specific file hashes or registry keys) to scan for known malware variants during a quarterly threat hunt.

  • Filter/Exclusion: Exclude processes originating from the security tool’s binary path (e.g., C:\Program Files\YARA\yara.exe or C:\Tools\Sigma\sigma-runner.exe) or exclude events where the parent process is a known security management console (e.g., SIEM-agent.exe, CrowdStrike-Service.exe).

• Scenario: An IT administrator manually copies a sample file of the Hook malware (or a known benign file with the same hash due to a collision) to a test VM or jump host for analysis and documentation purposes.

  • Filter/Exclusion: Exclude events where the file path resides in dedicated analysis directories (e.g., C:\Temp\Analysis\, C:\Users\Admin\Desktop\IOCs\) or where the user account belongs to a specific security/admin group (e.g., SecurityOps, ITAdmins).

• Scenario: A software update or patching tool (such as SCCM, PDQ Deploy, or Ansible) pushes a configuration file or script that contains the Hook IOC string as part of a detection template or documentation comment within a deployed YAML/JSON file.

  • Filter/Exclusion: Exclude events where the parent process is a deployment agent (e.g., ccmexec.exe, pdqdeploy.exe, ansible-playbook.exe) or where the file extension is a configuration type (.yaml, .json, .xml) and the file size is small (< 10KB).

• Scenario: A developer or QA engineer uses a version control system (Git) to commit a test script or unit test