Browser Extension Install

 1[metadata]
 2creation_date = "2023/08/22"
 3integration = ["endpoint"]
 4maturity = "production"
 5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
 6min_stack_version = "8.3.0"
 7updated_date = "2024/04/05"
 8
 9[rule]
10author = ["Elastic"]
11description = """
12Identifies the install of browser extensions. Malicious browser extensions can be installed via app store downloads
13masquerading as legitimate extensions, social engineering, or by an adversary that has already compromised a system.
14"""
15from = "now-9m"
16index = ["logs-endpoint.events.file-*"]
17language = "eql"
18license = "Elastic License v2"
19name = "Browser Extension Install"
20risk_score = 21
21rule_id = "f97504ac-1053-498f-aeaa-c6d01e76b379"
22severity = "low"
23tags = ["Domain: Endpoint", "OS: Windows", "Use Case: Threat Detection", "Tactic: Persistence", "Data Source: Elastic Defend"]
24timestamp_override = "event.ingested"
25type = "eql"
26
27query = '''
28file where host.os.type == "windows" and event.action : "creation" and 
29(
30  /* Firefox-Based Browsers */
31  (
32    file.name : "*.xpi" and
33    file.path : "?:\\Users\\*\\AppData\\Roaming\\*\\Profiles\\*\\Extensions\\*.xpi" and
34    not 
35    (
36      process.name : "firefox.exe" and
37      file.name : ("langpack-*@firefox.mozilla.org.xpi", "*@dictionaries.addons.mozilla.org.xpi")
38    )
39  ) or
40  /* Chromium-Based Browsers */
41  (
42    file.name : "*.crx" and
43    file.path : "?:\\Users\\*\\AppData\\Local\\*\\*\\User Data\\Webstore Downloads\\*"
44  )
45)
46'''
47
48[[rule.threat]]
49framework = "MITRE ATT&CK"
50[[rule.threat.technique]]
51id = "T1176"
52name = "Browser Extensions"
53reference = "https://attack.mitre.org/techniques/T1176/"
54
55[rule.threat.tactic]
56id = "TA0003"
57name = "Persistence"
58reference = "https://attack.mitre.org/tactics/TA0003/"