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SOCKS Traffic from an Unusual Process

This detection correlates FortiGate's application control SOCKS events with Elastic Defend network event to identify the source process performing SOCKS traffic. Adversaries may use a connection proxy to direct network traffic between systems or act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure.

Rule type: eql
Rule indices:

  • logs-endpoint.events.network-*
  • logs-fortinet_fortigate.log-*

Rule Severity: medium
Risk Score: 47
Runs every:
Searches indices from: now-9m
Maximum alerts per execution: ?
References:

Tags:

  • Domain: Endpoint
  • OS: Linux
  • OS: Windows
  • OS: macOS
  • Use Case: Threat Detection
  • Tactic: Command and Control
  • Data Source: Elastic Defend
  • Data Source: Fortinet
  • Resources: Investigation Guide

Version: ?
Rule authors:

  • Elastic

Rule license: Elastic License v2

  • Review the process details like command_line, privileges, global relevance and reputation.
  • Review the parent process execution details like command_line, global relevance and reputation.
  • Examine all network connection details performed by the process during last 48h.
  • Examine all localhost network connections performed by the same process to verify if there is any port forwarding with another process on the same machine.
  • Correlate the alert with other security events or logs to identify any patterns or additional indicators of compromise related to the same process or network activity.
  • Browser proxy extensions and Add-ons.
  • Development and deployment tools.
  • Third party trusted tools using SOCKS for network communication.
  • Immediately isolate the affected system from the network to prevent further unauthorized access or data exfiltration.
  • Terminate the suspicious processes and all associated children and parents.
  • Conduct a thorough review of the system's configuration files to identify unauthorized changes.
  • Reset credentials for any accounts associated with the source machine.
  • Implement network-level controls to block traffic via SOCKS unless authorized.
  • Escalate the incident to the security operations center (SOC) or incident response team for further investigation and to determine if additional systems are affected.
sequence by source.port, source.ip, destination.ip with maxspan=1m
 [network where event.dataset == "fortinet_fortigate.log" and event.action == "signature" and network.application in ("SOCKS4", "SOCKS5")]
 [network where event.module == "endpoint" and event.action in ("disconnect_received", "connection_attempted")]

Framework: MITRE ATT&CK