[New Rule] Pluggable Authentication Module Source Download (#4301)

* [New Rule] Pluggable Authentication Module Source Download

* Update persistence_pluggable_authentication_module_source_download.toml

* Update rules/linux/persistence_pluggable_authentication_module_source_download.toml

rules/linux/persistence_pluggable_authentication_module_source_download.toml

@@ -0,0 +1,72 @@
+[metadata]
+creation_date = "2024/12/16"
+integration = ["endpoint"]
+maturity = "production"
+updated_date = "2024/12/16"
+
+[rule]
+author = ["Elastic"]
+description = """
+This rule detects the usage of `curl` or `wget` to download the source code of a Pluggable Authentication Module (PAM)
+shared object file. Attackers may download the source code of a PAM shared object file to create a backdoor in the
+authentication process.
+"""
+false_positives = [
+    "Trusted system module updates or allowed Pluggable Authentication Module (PAM) daemon configuration changes.",
+]
+from = "now-9m"
+index = ["logs-endpoint.events.process*", "endgame-*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Pluggable Authentication Module (PAM) Source Download"
+references = [
+    "https://github.com/zephrax/linux-pam-backdoor",
+    "https://github.com/eurialo/pambd",
+    "http://0x90909090.blogspot.com/2016/06/creating-backdoor-in-pam-in-5-line-of.html",
+    "https://www.trendmicro.com/en_us/research/19/i/skidmap-linux-malware-uses-rootkit-capabilities-to-hide-cryptocurrency-mining-payload.html",
+]
+risk_score = 21
+rule_id = "53ef31ea-1f8a-493b-9614-df23d8277232"
+severity = "low"
+tags = [
+    "Domain: Endpoint",
+    "OS: Linux",
+    "Use Case: Threat Detection",
+    "Tactic: Credential Access",
+    "Tactic: Persistence",
+    "Data Source: Elastic Defend",
+    "Data Source: Elastic Endgame",
+]
+timestamp_override = "event.ingested"
+type = "eql"
+query = '''
+process where host.os.type == "linux" and event.type == "start" and event.action in ("exec", "exec_event") and
+process.name in ("curl", "wget") and
+process.args like~ "https://github.com/linux-pam/linux-pam/releases/download/v*/Linux-PAM-*.tar.xz"
+'''
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1543"
+name = "Create or Modify System Process"
+reference = "https://attack.mitre.org/techniques/T1543/"
+
+[rule.threat.tactic]
+id = "TA0003"
+name = "Persistence"
+reference = "https://attack.mitre.org/tactics/TA0003/"
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1556"
+name = "Modify Authentication Process"
+reference = "https://attack.mitre.org/techniques/T1556/"
+
+[rule.threat.tactic]
+id = "TA0006"
+name = "Credential Access"
+reference = "https://attack.mitre.org/tactics/TA0006/"