Potential Privilege Escalation via OverlayFS

 1[metadata]
 2creation_date = "2023/07/28"
 3integration = ["endpoint"]
 4maturity = "production"
 5updated_date = "2024/05/21"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10Identifies an attempt to exploit a local privilege escalation (CVE-2023-2640 and CVE-2023-32629) via a flaw in Ubuntu's
11modifications to OverlayFS. These flaws allow the creation of specialized executables, which, upon execution, grant the
12ability to escalate privileges to root on the affected machine.
13"""
14from = "now-9m"
15index = ["logs-endpoint.events.*"]
16language = "eql"
17license = "Elastic License v2"
18name = "Potential Privilege Escalation via OverlayFS"
19references = [
20    "https://www.wiz.io/blog/ubuntu-overlayfs-vulnerability",
21    "https://twitter.com/liadeliyahu/status/1684841527959273472",
22]
23risk_score = 73
24rule_id = "b51dbc92-84e2-4af1-ba47-65183fcd0c57"
25setup = """## Setup
26
27This rule requires data coming in from Elastic Defend.
28
29### Elastic Defend Integration Setup
30Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.
31
32#### Prerequisite Requirements:
33- Fleet is required for Elastic Defend.
34- To configure Fleet Server refer to the [documentation](https://www.elastic.co/guide/en/fleet/current/fleet-server.html).
35
36#### The following steps should be executed in order to add the Elastic Defend integration on a Linux System:
37- Go to the Kibana home page and click "Add integrations".
38- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
39- Click "Add Elastic Defend".
40- Configure the integration name and optionally add a description.
41- Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
42- Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. [Helper guide](https://www.elastic.co/guide/en/security/current/configure-endpoint-integration-policy.html).
43- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
44- Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead.
45For more details on Elastic Agent configuration settings, refer to the [helper guide](https://www.elastic.co/guide/en/fleet/8.10/agent-policy.html).
46- Click "Save and Continue".
47- To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts.
48For more details on Elastic Defend refer to the [helper guide](https://www.elastic.co/guide/en/security/current/install-endpoint.html).
49"""
50severity = "high"
51tags = [
52    "Domain: Endpoint",
53    "OS: Linux",
54    "Use Case: Threat Detection",
55    "Tactic: Privilege Escalation",
56    "Use Case: Vulnerability",
57    "Data Source: Elastic Defend",
58]
59type = "eql"
60
61query = '''
62sequence by process.parent.entity_id, host.id with maxspan=5s
63  [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and 
64    process.name == "unshare" and process.args : ("-r", "-rm", "m") and process.args : "*cap_setuid*"  and user.id != "0"]
65  [process where host.os.type == "linux" and event.action == "uid_change" and event.type == "change" and 
66    user.id == "0"]
67'''
68
69
70[[rule.threat]]
71framework = "MITRE ATT&CK"
72[[rule.threat.technique]]
73id = "T1068"
74name = "Exploitation for Privilege Escalation"
75reference = "https://attack.mitre.org/techniques/T1068/"
76
77
78[rule.threat.tactic]
79id = "TA0004"
80name = "Privilege Escalation"
81reference = "https://attack.mitre.org/tactics/TA0004/"