Ruben Groenewoud
67 lines
1.9 KiB
TOML
67 lines
1.9 KiB
TOML
[metadata]
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creation_date = "2025/04/30"
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integration = ["endpoint"]
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maturity = "production"
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updated_date = "2025/04/30"
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[rule]
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author = ["Elastic"]
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description = """
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This rule detects the execution of unusual commands via a descendant process of exim4. Attackers may use descendant
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processes of exim4 to evade detection and establish persistence or execute post-exploitation commands on a target system.
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"""
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from = "now-9m"
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index = ["logs-endpoint.events.process*"]
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language = "kuery"
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license = "Elastic License v2"
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name = "Unusual Exim4 Child Process"
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references = [
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"https://www.qualys.com/2021/05/04/21nails/21nails.txt",
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"https://blog.qualys.com/vulnerabilities-threat-research/2021/05/04/21nails-multiple-vulnerabilities-in-exim-mail-server"
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]
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risk_score = 21
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rule_id = "6eb862bb-013d-4d4f-a14b-341433ca1a1f"
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severity = "low"
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tags = [
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"Domain: Endpoint",
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"OS: Linux",
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"Use Case: Threat Detection",
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"Tactic: Persistence",
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"Data Source: Elastic Defend",
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]
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timestamp_override = "event.ingested"
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type = "new_terms"
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query = '''
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host.os.type:linux and event.type:start and event.action:exec and process.parent.name:exim4 and
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not process.name:(
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exim4 or start-stop-daemon or run-parts or systemctl or update-exim4.conf or install or plymouth or
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readlink or grep or stat or cmake or gcc or cppcheck or sort or sshd
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)
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'''
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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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id = "T1037"
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name = "Boot or Logon Initialization Scripts"
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reference = "https://attack.mitre.org/techniques/T1037/"
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[[rule.threat.technique]]
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id = "T1554"
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name = "Compromise Host Software Binary"
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reference = "https://attack.mitre.org/techniques/T1554/"
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[rule.threat.tactic]
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id = "TA0003"
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name = "Persistence"
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reference = "https://attack.mitre.org/tactics/TA0003/"
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[rule.new_terms]
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field = "new_terms_fields"
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value = ["process.executable"]
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[[rule.new_terms.history_window_start]]
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field = "history_window_start"
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value = "now-14d"
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