Detect Mount Execution With Hidepid Parameter (#2706)

rules/linux/defense_evasion_mount_execution.toml

@@ -0,0 +1,52 @@
+[metadata]
+creation_date = "2023/04/11"
+integration = ["endpoint"]
+maturity = "production"
+min_stack_comments = "New fields added: required_fields, related_integrations, setup"
+min_stack_version = "8.3.0"
+updated_date = "2023/04/11"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies the execution of mount process with hidepid parameter, which can make processes invisible to
+other users from the system. Adversaries using Linux kernel version 3.2+ (or RHEL/CentOS v6.5+ above) can hide
+the process from other users. When hidepid=2 option is executed to mount the /proc filesystem, only the root user
+can see all processes and the logged-in user can only see their own process. This provides a defense evasion mechanism for
+the adversaries to hide their process executions from all other commands such as ps, top, pgrep and more.
+With the Linux kernel hardening hidepid option all the user has to do is remount the /proc filesystem with the option,
+which can now be monitored and detected.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Potential Hidden Process via Mount Hidepid"
+references = [
+    "https://www.cyberciti.biz/faq/linux-hide-processes-from-other-users/",
+]
+risk_score = 47
+rule_id = "dc71c186-9fe4-4437-a4d0-85ebb32b8204"
+severity = "medium"
+tags = ["Elastic", "Host", "Linux", "Threat Detection", "Defense Evasion"]
+timestamp_override = "event.ingested"
+type = "eql"
+query = '''
+process where process.name=="mount" and event.action =="exec" and
+    process.args: ( "/proc") and process.args: ("-o") and process.args:("*hidepid=2*") and
+    host.os.type == "linux"
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1564"
+name = "Hide Artifacts"
+reference = "https://attack.mitre.org/techniques/T1564/"
+
+
+[rule.threat.tactic]
+id = "TA0005"
+name = "Defense Evasion"
+reference = "https://attack.mitre.org/tactics/TA0005/"