[New Rule] Insmod kernel module load (#2093)

* insmod kernel module load

* Update rules/linux/persistence_insmod_kernel_module_load.toml

* Update rules/linux/persistence_insmod_kernel_module_load.toml

(cherry picked from commit d7d0466344)

rules/linux/persistence_insmod_kernel_module_load.toml

@@ -0,0 +1,46 @@
+[metadata]
+creation_date = "2022/07/11"
+maturity = "production"
+updated_date = "2022/07/11"
+
+[rule]
+author = ["Elastic"]
+description = """
+Detects the use of the insmod binary to load a Linux kernel object file. Threat actors can use this binary, given they have root privileges, to load a rootkit on a system providing them with complete control and the ability to hide from security products. Manually loading a kernel module in this manner should not be at all common and can indicate suspcious or malicious behavior. 
+"""
+from = "now-9m"
+index = ["logs-*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Kernel module load via insmod"
+references = [
+    "https://decoded.avast.io/davidalvarez/linux-threat-hunting-syslogk-a-kernel-rootkit-found-under-development-in-the-wild/"
+]
+risk_score = 85
+rule_id = "2339f03c-f53f-40fa-834b-40c5983fc41f"
+severity = "medium"
+tags = ["Elastic", "Host", "Linux", "Threat Detection", "Persistence", "Rootkit"]
+timestamp_override = "event.ingested"
+type = "eql"
+
+query = '''
+process where event.type == "start" and process.executable : "/usr/sbin/insmod" and process.args : "*.ko"
+'''
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1547"
+name = "Boot or Logon Autostart Execution"
+reference = "https://attack.mitre.org/techniques/T1547/"
+
+[[rule.threat.technique.subtechnique]]
+id = "T1547.006"
+name = "Kernel Modules and Extensions"
+reference = "https://attack.mitre.org/techniques/T1547/006/"
+
+[rule.threat.tactic]
+id = "TA0003"
+name = "Persistence"
+reference = "https://attack.mitre.org/tactics/TA0003/"
+