Perl Outbound Network Connection

Detects when Perl makes an outbound network connection to a non-private IP address. Perl is a scripting language that comes pre-installed on macOS and offers extensive capabilities for adversaries. Its use for network connections on macOS systems is uncommon and potentially suspicious.

Rule type: eql
Rule indices:

• logs-endpoint.events.network-*
• logs-endpoint.events.process-*

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

Tags:

• Domain: Endpoint
• OS: macOS
• Use Case: Threat Detection
• Tactic: Command and Control
• Tactic: Execution
• Data Source: Elastic Defend

Version: ?
Rule authors:

• Elastic

Rule license: Elastic License v2

sequence by process.entity_id with maxspan=30s
  [process where host.os.type == "macos" and event.type == "start" and event.action == "exec" and
    process.name == "perl" and not process.args like "/usr/bin/xpath"]
  [network where host.os.type == "macos" and event.type == "start" and process.name == "perl" and
    not cidrmatch(destination.ip,
        "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12",
        "192.0.0.0/24", "192.0.2.0/24", "192.168.0.0/16", "192.88.99.0/24",
        "224.0.0.0/4", "240.0.0.0/4", "::1", "FE80::/10", "FF00::/8")]
		

Framework: MITRE ATT&CK

• Tactic:

  • Name: Command and Control
  • Id: TA0011
  • Reference URL: https://attack.mitre.org/tactics/TA0011/

• Technique:

  • Name: Application Layer Protocol
  • Id: T1071
  • Reference URL: https://attack.mitre.org/techniques/T1071/

• Sub Technique:

  • Name: Web Protocols
  • Id: T1071.001
  • Reference URL: https://attack.mitre.org/techniques/T1071/001/

Framework: MITRE ATT&CK

• Tactic:

  • Name: Execution
  • Id: TA0002
  • Reference URL: https://attack.mitre.org/tactics/TA0002/

• Technique:

  • Name: Command and Scripting Interpreter
  • Id: T1059
  • Reference URL: https://attack.mitre.org/techniques/T1059/