Unsigned DLL Side-Loading from a Suspicious Folder

Last updated 7 months ago on 2025-01-15
Created 3 years ago on 2022-11-22

About

Identifies a Windows trusted program running from locations often abused by adversaries to masquerade as a trusted program and loading a recently dropped DLL. This behavior may indicate an attempt to evade defenses via side-loading a malicious DLL within the memory space of a signed processes.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Defense EvasionData Source: Elastic DefendLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Defense Evasion (TA0005)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.library-*
Related Integrations

endpoint(opens in a new tab or window)

Query
library where host.os.type == "windows" and

 process.code_signature.trusted == true and

 (dll.Ext.relative_file_creation_time <= 500 or dll.Ext.relative_file_name_modify_time <= 500) and

  not dll.code_signature.status : ("trusted", "errorExpired", "errorCode_endpoint*", "errorChaining") and

      /* Suspicious Paths */
      dll.path : ("?:\\PerfLogs\\*.dll",
                  "?:\\Users\\*\\Pictures\\*.dll",
                  "?:\\Users\\*\\Music\\*.dll",
                  "?:\\Users\\Public\\*.dll",
                  "?:\\Users\\*\\Documents\\*.dll",
                  "?:\\Windows\\Tasks\\*.dll",
                  "?:\\Windows\\System32\\Tasks\\*.dll",
                  "?:\\Intel\\*.dll",
                  "?:\\AMD\\Temp\\*.dll",
                  "?:\\Windows\\AppReadiness\\*.dll",
                  "?:\\Windows\\ServiceState\\*.dll",
                  "?:\\Windows\\security\\*.dll",
		  "?:\\Windows\\System\\*.dll",
                  "?:\\Windows\\IdentityCRL\\*.dll",
                  "?:\\Windows\\Branding\\*.dll",
                  "?:\\Windows\\csc\\*.dll",
                  "?:\\Windows\\DigitalLocker\\*.dll",
                  "?:\\Windows\\en-US\\*.dll",
                  "?:\\Windows\\wlansvc\\*.dll",
                  "?:\\Windows\\Prefetch\\*.dll",
                  "?:\\Windows\\Fonts\\*.dll",
                  "?:\\Windows\\diagnostics\\*.dll",
                  "?:\\Windows\\TAPI\\*.dll",
                  "?:\\Windows\\INF\\*.dll",
                  "?:\\windows\\tracing\\*.dll",
                  "?:\\windows\\IME\\*.dll",
                  "?:\\Windows\\Performance\\*.dll",
                  "?:\\windows\\intel\\*.dll",
                  "?:\\windows\\ms\\*.dll",
                  "?:\\Windows\\dot3svc\\*.dll",
                  "?:\\Windows\\ServiceProfiles\\*.dll",
                  "?:\\Windows\\panther\\*.dll",
                  "?:\\Windows\\RemotePackages\\*.dll",
                  "?:\\Windows\\OCR\\*.dll",
                  "?:\\Windows\\appcompat\\*.dll",
                  "?:\\Windows\\apppatch\\*.dll",
                  "?:\\Windows\\addins\\*.dll",
                  "?:\\Windows\\Setup\\*.dll",
                  "?:\\Windows\\Help\\*.dll",
                  "?:\\Windows\\SKB\\*.dll",
                  "?:\\Windows\\Vss\\*.dll",
                  "?:\\Windows\\Web\\*.dll",
                  "?:\\Windows\\servicing\\*.dll",
                  "?:\\Windows\\CbsTemp\\*.dll",
                  "?:\\Windows\\Logs\\*.dll",
                  "?:\\Windows\\WaaS\\*.dll",
                  "?:\\Windows\\twain_32\\*.dll",
                  "?:\\Windows\\ShellExperiences\\*.dll",
                  "?:\\Windows\\ShellComponents\\*.dll",
                  "?:\\Windows\\PLA\\*.dll",
                  "?:\\Windows\\Migration\\*.dll",
                  "?:\\Windows\\debug\\*.dll",
                  "?:\\Windows\\Cursors\\*.dll",
                  "?:\\Windows\\Containers\\*.dll",
                  "?:\\Windows\\Boot\\*.dll",
                  "?:\\Windows\\bcastdvr\\*.dll",
                  "?:\\Windows\\TextInput\\*.dll",
                  "?:\\Windows\\schemas\\*.dll",
                  "?:\\Windows\\SchCache\\*.dll",
                  "?:\\Windows\\Resources\\*.dll",
                  "?:\\Windows\\rescache\\*.dll",
                  "?:\\Windows\\Provisioning\\*.dll",
                  "?:\\Windows\\PrintDialog\\*.dll",
                  "?:\\Windows\\PolicyDefinitions\\*.dll",
                  "?:\\Windows\\media\\*.dll",
                  "?:\\Windows\\Globalization\\*.dll",
                  "?:\\Windows\\L2Schemas\\*.dll",
                  "?:\\Windows\\LiveKernelReports\\*.dll",
                  "?:\\Windows\\ModemLogs\\*.dll",
                  "?:\\Windows\\ImmersiveControlPanel\\*.dll",
                  "?:\\$Recycle.Bin\\*.dll") and

	 /* DLL loaded from the process.executable current directory */
	 endswith~(substring(dll.path, 0, length(dll.path) - (length(dll.name) + 1)), substring(process.executable, 0, length(process.executable) - (length(process.name) + 1)))

Install detection rules in Elastic Security

Detect Unsigned DLL Side-Loading from a Suspicious Folder in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).