Execution via local SxS Shared Module

 1[metadata]
 2creation_date = "2020/10/28"
 3integration = ["endpoint", "windows", "m365_defender", "sentinel_one_cloud_funnel"]
 4maturity = "production"
 5updated_date = "2025/03/20"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10Identifies the creation, change, or deletion of a DLL module within a Windows SxS local folder. Adversaries may abuse
11shared modules to execute malicious payloads by instructing the Windows module loader to load DLLs from arbitrary local
12paths.
13"""
14from = "now-9m"
15index = [
16    "winlogbeat-*",
17    "logs-endpoint.events.file-*",
18    "logs-windows.sysmon_operational-*",
19    "endgame-*",
20    "logs-m365_defender.event-*",
21    "logs-sentinel_one_cloud_funnel.*",
22]
23language = "eql"
24license = "Elastic License v2"
25name = "Execution via local SxS Shared Module"
26note = """## Triage and analysis
27
28The SxS DotLocal folder is a legitimate feature that can be abused to hijack standard modules loading order by forcing an executable on the same application.exe.local folder to load a malicious DLL module from the same directory.
29"""
30references = ["https://docs.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-redirection"]
31risk_score = 47
32rule_id = "a3ea12f3-0d4e-4667-8b44-4230c63f3c75"
33severity = "medium"
34tags = [
35    "Domain: Endpoint",
36    "OS: Windows",
37    "Use Case: Threat Detection",
38    "Tactic: Execution",
39    "Data Source: Elastic Endgame",
40    "Data Source: Elastic Defend",
41    "Data Source: Sysmon",
42    "Data Source: Microsoft Defender for Endpoint",
43    "Data Source: SentinelOne",
44    "Resources: Investigation Guide",
45]
46timestamp_override = "event.ingested"
47type = "eql"
48
49query = '''
50file where host.os.type == "windows" and file.extension : "dll" and file.path : "C:\\*\\*.exe.local\\*.dll"
51'''
52
53
54[[rule.threat]]
55framework = "MITRE ATT&CK"
56[[rule.threat.technique]]
57id = "T1129"
58name = "Shared Modules"
59reference = "https://attack.mitre.org/techniques/T1129/"
60
61
62[rule.threat.tactic]
63id = "TA0002"
64name = "Execution"
65reference = "https://attack.mitre.org/tactics/TA0002/"