Browser Extension Install

 1[metadata]
 2creation_date = "2023/08/22"
 3integration = ["endpoint", "m365_defender", "sentinel_one_cloud_funnel", "windows"]
 4maturity = "production"
 5updated_date = "2024/10/15"
 6min_stack_version = "8.14.0"
 7min_stack_comments = "Breaking change at 8.14.0 for the Windows 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 = [
17    "logs-endpoint.events.file-*",
18    "logs-m365_defender.event-*",
19    "logs-sentinel_one_cloud_funnel.*",
20    "logs-windows.sysmon_operational-*",
21    "winlogbeat-*",
22    "endgame-*"
23]
24language = "eql"
25license = "Elastic License v2"
26name = "Browser Extension Install"
27risk_score = 21
28rule_id = "f97504ac-1053-498f-aeaa-c6d01e76b379"
29severity = "low"
30tags = [
31    "Domain: Endpoint",
32    "OS: Windows",
33    "Use Case: Threat Detection",
34    "Tactic: Persistence",
35    "Data Source: Elastic Defend",
36    "Data Source: Elastic Endgame",
37    "Data Source: SentinelOne",
38    "Data Source: Sysmon",
39    "Data Source: Microsoft Defender for Endpoint",
40]
41timestamp_override = "event.ingested"
42type = "eql"
43
44query = '''
45file where host.os.type == "windows" and event.type : "creation" and 
46(
47  /* Firefox-Based Browsers */
48  (
49    file.name : "*.xpi" and
50    file.path : "?:\\Users\\*\\AppData\\Roaming\\*\\Profiles\\*\\Extensions\\*.xpi" and
51    not 
52    (
53      process.name : "firefox.exe" and
54      file.name : ("langpack-*@firefox.mozilla.org.xpi", "*@dictionaries.addons.mozilla.org.xpi")
55    )
56  ) or
57  /* Chromium-Based Browsers */
58  (
59    file.name : "*.crx" and
60    file.path : "?:\\Users\\*\\AppData\\Local\\*\\*\\User Data\\Webstore Downloads\\*"
61  )
62)
63'''
64
65
66[[rule.threat]]
67framework = "MITRE ATT&CK"
68[[rule.threat.technique]]
69id = "T1176"
70name = "Browser Extensions"
71reference = "https://attack.mitre.org/techniques/T1176/"
72
73
74[rule.threat.tactic]
75id = "TA0003"
76name = "Persistence"
77reference = "https://attack.mitre.org/tactics/TA0003/"