crash shell evasion threat (#1861)

(cherry picked from commit 22367d3702)

rules/linux/execution_crash_binary.toml

@@ -0,0 +1,51 @@
+[metadata]
+creation_date = "2022/03/21"
+maturity = "production"
+updated_date = "2022/03/21"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies Linux binary crash abuse to break out from restricted environments by spawning an interactive system
+shell.The crash utility helps to analyze Linux crash dump data or a live system and the activity of spawing a shell is
+not a standard use of this binary by a user or system administrator. It indicates a potentially malicious actor
+attempting to improve the capabilities or stability of their access.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Linux Restricted Shell Breakout via crash Shell evasion"
+references = ["https://gtfobins.github.io/gtfobins/crash/"]
+risk_score = 47
+rule_id = "ee619805-54d7-4c56-ba6f-7717282ddd73"
+severity = "medium"
+tags = ["Elastic", "Host", "Linux", "Threat Detection", "Execution", "GTFOBins"]
+timestamp_override = "event.ingested"
+type = "eql"
+
+query = '''
+sequence by host.id, process.pid with maxspan=1m
+[process where event.type == "start" and process.name == "crash" and process.args : "-h"]
+[process where process.parent.name == "crash" and process.name : "sh"]
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1059"
+name = "Command and Scripting Interpreter"
+reference = "https://attack.mitre.org/techniques/T1059/"
+[[rule.threat.technique.subtechnique]]
+id = "T1059.004"
+name = "Unix Shell"
+reference = "https://attack.mitre.org/techniques/T1059/004/"
+
+
+
+[rule.threat.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"
+