ZXProxy

Hunt Hypothesis

The ZXProxy rule detects potential proxy or tunneling activity that could be used to exfiltrate data or bypass network restrictions. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage adversarial communication that may evade traditional detection methods.

YARA Rule

rule ZXProxy
{
meta:
	author = "ThreatConnect Intelligence Research Team"
	
strings:
	$C = "\\Control\\zxplug" nocase wide ascii
	$h = "http://www.facebook.com/comment/update.exe" wide ascii
	$S = "Shared a shell to %s:%s Successfully" nocase wide ascii
condition:
	any 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 3 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled System Maintenance Task
  Description: A legitimate scheduled task runs a script that temporarily uses a proxy or connects through a known proxy tool during maintenance.
  Filter/Exclusion: Exclude processes associated with schtasks.exe or Task Scheduler using the process.parent_process field.

• Scenario: Admin Using ZXProxy for Debugging
  Description: A system administrator uses ZXProxy (a legitimate tool) to debug network traffic or test proxy configurations.
  Filter/Exclusion: Exclude processes where the process.user field matches known admin accounts or use process.name to filter out ZXProxy.exe.

• Scenario: Automated Backup Job Using Proxy
  Description: A backup tool (e.g., Veeam, Acronis) uses a proxy during data transfer as part of its configuration.
  Filter/Exclusion: Exclude processes with process.name matching backup tools or use process.command_line to identify backup-related commands.

• Scenario: Network Monitoring Tool Using Proxy
  Description: A network monitoring tool (e.g., Wireshark, tcpdump) is configured to route traffic through a proxy for analysis.
  Filter/Exclusion: Exclude processes with process.name matching network analysis tools or use process.command_line to identify proxy-related flags.

• Scenario: Internal Proxy Server Configuration
  Description: An internal proxy server (e.g., Squid, NGINX) is configured to handle internal traffic and is detected by the rule.
  Filter/Exclusion: Exclude processes where the process.name matches known proxy servers or use process.parent_process to identify internal service calls.