Quarantine Attrib Removed by Unsigned or Untrusted Process

 1[metadata]
 2creation_date = "2020/08/14"
 3integration = ["endpoint"]
 4maturity = "production"
 5updated_date = "2024/05/21"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10Detects deletion of the quarantine attribute by an unusual process (xattr). In macOS, when applications or programs are
11downloaded from the internet, there is a quarantine flag set on the file. This attribute is read by Apple's Gatekeeper
12defense program at execution time. An adversary may disable this attribute to evade defenses.
13"""
14from = "now-9m"
15index = ["logs-endpoint.events.*"]
16language = "eql"
17license = "Elastic License v2"
18name = "Quarantine Attrib Removed by Unsigned or Untrusted Process"
19references = [
20    "https://nixhacker.com/security-protection-in-macos-1/",
21    "https://eclecticlight.co/2020/10/29/quarantine-and-the-quarantine-flag/",
22]
23risk_score = 47
24rule_id = "f0b48bbc-549e-4bcf-8ee0-a7a72586c6a7"
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 macOS 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, for MacOS it is recommended to select "Traditional Endpoints".
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/current/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 = "medium"
51tags = [
52    "Domain: Endpoint",
53    "OS: macOS",
54    "Use Case: Threat Detection",
55    "Tactic: Defense Evasion",
56    "Data Source: Elastic Defend",
57]
58timestamp_override = "event.ingested"
59type = "eql"
60
61query = '''
62file where event.action == "extended_attributes_delete" and host.os.type == "macos" and process.executable != null and
63(process.code_signature.trusted == false or process.code_signature.exists == false) and not
64process.executable : ("/usr/bin/xattr", 
65                      "/System/*", 
66                      "/private/tmp/KSInstallAction.*/*/Install Google Software Update.app/Contents/Helpers/ksinstall",
67                      "/Applications/CEWE Fotoschau.app/Contents/MacOS/FotoPlus",
68                      "/Applications/.com.bomgar.scc.*/Remote Support Customer Client.app/Contents/MacOS/sdcust") and not
69file.path : "/private/var/folders/*"
70'''
71
72
73[[rule.threat]]
74framework = "MITRE ATT&CK"
75[[rule.threat.technique]]
76id = "T1562"
77name = "Impair Defenses"
78reference = "https://attack.mitre.org/techniques/T1562/"
79[[rule.threat.technique.subtechnique]]
80id = "T1562.001"
81name = "Disable or Modify Tools"
82reference = "https://attack.mitre.org/techniques/T1562/001/"
83
84
85
86[rule.threat.tactic]
87id = "TA0005"
88name = "Defense Evasion"
89reference = "https://attack.mitre.org/tactics/TA0005/"