[New Rules] Docker Entrypoint Netcon / Nsenter Escape (elastic#3883)

* [New Rules] Docker entrypoint netcon / nsenter escape

* ++

* Update privilege_escalation_docker_escape_via_nsenter.toml

* Update privilege_escalation_docker_escape_via_nsenter.toml

* Better description formatting

* Update execution_egress_connection_from_entrypoint_in_container.toml

* Update privilege_escalation_docker_escape_via_nsenter.toml

rules/linux/execution_egress_connection_from_entrypoint_in_container.toml

@@ -0,0 +1,77 @@
+[metadata]
+creation_date = "2024/07/10"
+integration = ["endpoint"]
+maturity = "production"
+updated_date = "2024/07/10"
+
+[rule]
+author = ["Elastic"]
+description = """
+This rule identifies a sequence of events where a process named `entrypoint.sh` is started in a container, followed by a
+network connection attempt. This sequence indicates a potential egress connection from an entrypoint in a container. An
+entrypoint is a command or script specified in the Dockerfile and executed when the container starts. Attackers can use
+this technique to establish a foothold in the environment, escape from a container to the host, or establish persistence.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Egress Connection from Entrypoint in Container"
+risk_score = 47
+rule_id = "c75d0c86-38d6-4821-98a1-465cff8ff4c8"
+severity = "medium"
+tags = [
+    "Domain: Endpoint",
+    "Domain: Container",
+    "OS: Linux",
+    "Use Case: Threat Detection",
+    "Tactic: Execution",
+    "Data Source: Elastic Defend",
+]
+timestamp_override = "event.ingested"
+type = "eql"
+query = '''
+sequence by host.id with maxspan=3s
+  [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
+   process.entry_leader.entry_meta.type == "container" and process.name == "entrypoint.sh"] by process.entity_id
+  [network where event.type == "start" and event.action == "connection_attempted" and not (
+     destination.ip == null or destination.ip == "0.0.0.0" or cidrmatch(
+       destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29",
+       "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
+       "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10",
+       "192.175.48.0/24","198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10",
+       "FF00::/8", "172.31.0.0/16"
+       )
+    )] by process.parent.entity_id
+'''
+
+[[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/"
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1611"
+name = "Escape to Host"
+reference = "https://attack.mitre.org/techniques/T1611/"
+
+[rule.threat.tactic]
+id = "TA0004"
+name = "Privilege Escalation"
+reference = "https://attack.mitre.org/tactics/TA0004/"

rules/linux/privilege_escalation_docker_escape_via_nsenter.toml

@@ -0,0 +1,50 @@
+[metadata]
+creation_date = "2024/07/10"
+integration = ["endpoint"]
+maturity = "production"
+updated_date = "2024/07/10"
+
+[rule]
+author = ["Elastic"]
+description = """
+This rule identifies a UID change event via `nsenter`. The `nsenter` command is used to enter a namespace, which is a
+way to isolate processes and resources. Attackers can use `nsenter` to escape from a container to the host, which can
+lead to privilege escalation and lateral movement.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.process*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Docker Escape via Nsenter"
+references = ["https://www.cyberark.com/resources/threat-research-blog/the-route-to-root-container-escape-using-kernel-exploitation"]
+risk_score = 47
+rule_id = "5f3ab3ce-7b41-4168-a06a-68d2af8ebc88"
+severity = "medium"
+tags = [
+    "Domain: Endpoint",
+    "Domain: Container",
+    "OS: Linux",
+    "Use Case: Threat Detection",
+    "Tactic: Privilege Escalation",
+    "Data Source: Elastic Defend",
+]
+timestamp_override = "event.ingested"
+type = "eql"
+query = '''
+process where host.os.type == "linux" and event.type == "change" and event.action == "uid_change" and
+process.entry_leader.entry_meta.type == "container" and process.args == "nsenter" and
+process.args in ("-t", "--target") and process.args_count >= 4
+'''
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1611"
+name = "Escape to Host"
+reference = "https://attack.mitre.org/techniques/T1611/"
+
+[rule.threat.tactic]
+id = "TA0004"
+name = "Privilege Escalation"
+reference = "https://attack.mitre.org/tactics/TA0004/"