Microsoft Build Engine Started by a System Process

 1[metadata]
 2creation_date = "2020/03/25"
 3integration = ["endpoint", "windows"]
 4maturity = "production"
 5updated_date = "2024/05/21"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10An instance of MSBuild, the Microsoft Build Engine, was started by Explorer or the WMI (Windows Management
11Instrumentation) subsystem. This behavior is unusual and is sometimes used by malicious payloads.
12"""
13false_positives = ["The Build Engine is commonly used by Windows developers but use by non-engineers is unusual."]
14from = "now-9m"
15index = [
16    "winlogbeat-*",
17    "logs-endpoint.events.process-*",
18    "logs-windows.*",
19    "endgame-*",
20    "logs-system.security*",
21]
22language = "eql"
23license = "Elastic License v2"
24name = "Microsoft Build Engine Started by a System Process"
25risk_score = 47
26rule_id = "9d110cb3-5f4b-4c9a-b9f5-53f0a1707ae3"
27setup = """## Setup
28
29If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
30events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
31Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
32`event.ingested` to @timestamp.
33For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
34"""
35severity = "medium"
36tags = [
37    "Domain: Endpoint",
38    "OS: Windows",
39    "Use Case: Threat Detection",
40    "Tactic: Defense Evasion",
41    "Tactic: Execution",
42    "Data Source: Elastic Endgame",
43    "Data Source: Elastic Defend",
44]
45timestamp_override = "event.ingested"
46type = "eql"
47
48query = '''
49process where host.os.type == "windows" and event.type == "start" and
50  process.name : "MSBuild.exe" and
51  process.parent.name : ("explorer.exe", "wmiprvse.exe")
52'''
53
54
55[[rule.threat]]
56framework = "MITRE ATT&CK"
57[[rule.threat.technique]]
58id = "T1127"
59name = "Trusted Developer Utilities Proxy Execution"
60reference = "https://attack.mitre.org/techniques/T1127/"
61[[rule.threat.technique.subtechnique]]
62id = "T1127.001"
63name = "MSBuild"
64reference = "https://attack.mitre.org/techniques/T1127/001/"
65
66
67
68[rule.threat.tactic]
69id = "TA0005"
70name = "Defense Evasion"
71reference = "https://attack.mitre.org/tactics/TA0005/"
72[[rule.threat]]
73framework = "MITRE ATT&CK"
74
75[rule.threat.tactic]
76id = "TA0002"
77name = "Execution"
78reference = "https://attack.mitre.org/tactics/TA0002/"