Browser Extension Install

 1[metadata]
 2creation_date = "2023/08/22"
 3integration = ["endpoint", "m365_defender", "sentinel_one_cloud_funnel"]
 4maturity = "production"
 5updated_date = "2024/10/10"
 6min_stack_version = "8.13.0"
 7min_stack_comments = "Breaking change at 8.13.0 for SentinelOne Integration."
 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-*", "logs-m365_defender.event-*", "logs-sentinel_one_cloud_funnel.*", "logs-windows.sysmon_operational-*"]
17language = "eql"
18license = "Elastic License v2"
19name = "Browser Extension Install"
20risk_score = 21
21rule_id = "f97504ac-1053-498f-aeaa-c6d01e76b379"
22severity = "low"
23tags = [
24    "Domain: Endpoint",
25    "OS: Windows",
26    "Use Case: Threat Detection",
27    "Tactic: Persistence",
28    "Data Source: Elastic Defend",
29    "Data Source: Microsoft Defender for Endpoint",
30    "Data Source: Sysmon",
31    "Data Source: SentinelOne",
32]
33timestamp_override = "event.ingested"
34type = "eql"
35
36query = '''
37file where host.os.type == "windows" and event.action : "creation" and 
38(
39  /* Firefox-Based Browsers */
40  (
41    file.name : "*.xpi" and
42    file.path : "?:\\Users\\*\\AppData\\Roaming\\*\\Profiles\\*\\Extensions\\*.xpi" and
43    not 
44    (
45      process.name : "firefox.exe" and
46      file.name : ("langpack-*@firefox.mozilla.org.xpi", "*@dictionaries.addons.mozilla.org.xpi")
47    )
48  ) or
49  /* Chromium-Based Browsers */
50  (
51    file.name : "*.crx" and
52    file.path : "?:\\Users\\*\\AppData\\Local\\*\\*\\User Data\\Webstore Downloads\\*"
53  )
54)
55'''
56
57
58[[rule.threat]]
59framework = "MITRE ATT&CK"
60[[rule.threat.technique]]
61id = "T1176"
62name = "Browser Extensions"
63reference = "https://attack.mitre.org/techniques/T1176/"
64
65
66[rule.threat.tactic]
67id = "TA0003"
68name = "Persistence"
69reference = "https://attack.mitre.org/tactics/TA0003/"