Detection of suspicious crontab creation or modification

rules/macos/persistence_crontab_creation.toml

@@ -0,0 +1,51 @@
+[metadata]
+creation_date = "2022/04/25"
+maturity = "production"
+updated_date = "2022/04/25"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies attempts to create or modify a crontab via a process that is not crontab (i.e python, osascript, etc.). This
+activity should not be highly prevalent and could indicate the use of cron as a persistence mechanism by a threat actor.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Suspicious CronTab Creation or Modification"
+references = [
+    "https://taomm.org/PDFs/vol1/CH%200x02%20Persistence.pdf",
+    "https://theevilbit.github.io/beyond/beyond_0004/",
+]
+risk_score = 47
+rule_id = "530178da-92ea-43ce-94c2-8877a826783d"
+severity = "medium"
+tags = ["Elastic", "Host", "macOS", "Threat Detection", "Persistence"]
+timestamp_override = "event.ingested"
+type = "eql"
+
+query = '''
+file where event.type != "deletion" and process.name != null and 
+  file.path : "/private/var/at/tabs/*" and not process.executable == "/usr/bin/crontab"
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1053"
+name = "Scheduled Task/Job"
+reference = "https://attack.mitre.org/techniques/T1053/"
+[[rule.threat.technique.subtechnique]]
+id = "T1053.003"
+name = "Cron"
+reference = "https://attack.mitre.org/techniques/T1053/003/"
+
+
+
+[rule.threat.tactic]
+id = "TA0003"
+name = "Persistence"
+reference = "https://attack.mitre.org/tactics/TA0003/"
+