Casper French Espionage Malware - System Info Output - http://goo.gl/VRJNLo

Hunt Hypothesis

Casper French Espionage Malware is exfiltrating system information via a known malicious URL, indicating potential data theft and reconnaissance by an advanced adversary. SOC teams should proactively hunt for this behavior in Azure Sentinel to detect and mitigate espionage activities before sensitive data is compromised.

YARA Rule

rule Casper_SystemInformation_Output
{

    meta:
        description = "Casper French Espionage Malware - System Info Output - http://goo.gl/VRJNLo"
        author = "Florian Roth"
        reference = "http://goo.gl/VRJNLo"
        date = "2015/03/06"
        score = 70

    strings:
        $a0 = "***** SYSTEM INFORMATION ******"
        $a1 = "***** SECURITY INFORMATION ******"
        $a2 = "Antivirus: "
        $a3 = "Firewall: "
        $a4 = "***** EXECUTION CONTEXT ******"
        $a5 = "Identity: "
        $a6 = "<CONFIG TIMESTAMP="

    condition:
        all of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 7 string patterns in its detection logic.

References

• http://goo.gl/VRJNLo
• Source Rule

False Positive Guidance

• Scenario: A system administrator is using PowerShell to gather system information for a routine health check.
  Filter/Exclusion: Exclude processes where the command line includes Get-WmiObject or Get-CimInstance and the user is a domain admin.

• Scenario: A scheduled task runs Sysmon (Microsoft Sysmon) to collect system event logs for compliance purposes.
  Filter/Exclusion: Exclude events where the source is Sysmon and the event ID corresponds to known Sysmon logging activities.

• Scenario: A Windows Update job is executing and temporarily writes system information to a log file for diagnostic purposes.
  Filter/Exclusion: Exclude processes with the executable path containing wuauclt.exe or WindowsUpdate.log.

• Scenario: A remote management tool like Microsoft Endpoint Manager (Intune) is collecting system metrics during a device compliance scan.
  Filter/Exclusion: Exclude processes where the parent process is msiexec.exe or the command line includes Intune or Microsoft Endpoint Manager.

• Scenario: A third-party monitoring tool such as SolarWinds is generating system info output as part of its normal monitoring operations.
  Filter/Exclusion: Exclude processes where the executable path contains SolarWinds or the command line includes Monitor or Collect.