sigma-rules/rules/windows/execution_shared_modules_local_sxs_dll.toml

[metadata]
creation_date = "2020/10/28"
maturity = "production"
updated_date = "2022/03/31"

[rule]
author = ["Elastic"]
description = """
Identifies the creation, change, or deletion of a DLL module within a Windows SxS local folder. Adversaries may abuse
shared modules to execute malicious payloads by instructing the Windows module loader to load DLLs from arbitrary local
paths.
"""
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Execution via local SxS Shared Module"
note = """## Triage and analysis

The 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.

## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
"""
references = ["https://docs.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-redirection"]
risk_score = 47
rule_id = "a3ea12f3-0d4e-4667-8b44-4230c63f3c75"
severity = "medium"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
file where file.extension : "dll" and file.path : "C:\\*\\*.exe.local\\*.dll"
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1129"
name = "Shared Modules"
reference = "https://attack.mitre.org/techniques/T1129/"


[rule.threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"