Connection to Commonly Abused Free SSL Certificate Providersedit
Identifies unusual processes connecting to domains using known free SSL certificates. Adversaries may employ a known encryption algorithm to conceal command and control traffic.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
Severity: low
Risk score: 21
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Command and Control
Version: 100 (version history)
Added (Elastic Stack release): 7.11.0
Last modified (Elastic Stack release): 8.5.0
Rule authors: Elastic
Rule license: Elastic License v2
Investigation guideedit
Rule queryedit
network where network.protocol == "dns" and /* Add new free SSL
certificate provider domains here */ dns.question.name :
("*letsencrypt.org", "*.sslforfree.com", "*.zerossl.com",
"*.freessl.org") and /* Native Windows process paths that are
unlikely to have network connections to domains secured using free SSL
certificates */ process.executable :
("C:\\Windows\\System32\\*.exe",
"C:\\Windows\\System\\*.exe",
"C:\\Windows\\SysWOW64\\*.exe",
"C:\\Windows\\Microsoft.NET\\Framework*\\*.exe",
"C:\\Windows\\explorer.exe",
"C:\\Windows\\notepad.exe") and /* Insert noisy false positives
here */ not process.name : ("svchost.exe", "MicrosoftEdge*.exe",
"msedge.exe")
Threat mappingedit
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/
-
Technique:
- Name: Encrypted Channel
- ID: T1573
- Reference URL: https://attack.mitre.org/techniques/T1573/
Rule version historyedit
- Version 100 (8.5.0 release)
-
- Formatting only
- Version 6 (8.4.0 release)
-
-
Updated query, changed from:
network where network.protocol == "dns" and /* Add new free SSL certificate provider domains here */ dns.question.name : ("*letsencrypt.org", "*.sslforfree.com", "*.zerossl.com", "*.freessl.org") and /* Native Windows process paths that are unlikely to have network connections to domains secured using free SSL certificates */ process.executable : ("C:\\Windows\\System32\\*.exe", "C:\\Windows\\System\\*.exe", "C:\\Windows\\SysWOW64\\*.exe", "C:\\Windows\\Microsoft.NET\\Framework*\\*.exe", "C:\\Windows\\explorer.exe", "C:\\Windows\\notepad.exe") and /* Insert noisy false positives here */ not process.name : ("svchost.exe", "MicrosoftEdge*.exe", "msedge.exe")
-
- Version 4 (8.2.0 release)
-
- Formatting only
- Version 3 (7.12.0 release)
-
- Formatting only
- Version 2 (7.11.2 release)
-
- Formatting only