CAPEC-641

Detailed Abstraction Level
Meta — Very abstract, high-level category
Standard — Specific enough to understand
Detailed — Tied to specific technique Stable MITRE CAPEC Status
Stable — Fully reviewed and complete
Draft — Under development
Incomplete — Partially defined
Deprecated — No longer recommended
Obsolete — Replaced by another CAPEC Likelihood: Low Severity: High
DLL Side-Loading

Description

An adversary places a malicious version of a Dynamic-Link Library (DLL) in the Windows Side-by-Side (WinSxS) directory to trick the operating system into loading this malicious DLL instead of a legitimate DLL. Programs specify the location of the DLLs to load via the use of WinSxS manifests or DLL redirection and if they aren't used then Windows searches in a predefined set of directories to locate the file. If the applications improperly specify a required DLL or WinSxS manifests aren't explicit about the characteristics of the DLL to be loaded, they can be vulnerable to side-loading.

Prerequisites

The target must fail to verify the integrity of the DLL before using them.

Mitigations

Prevent unknown DLLs from loading through using an allowlist policy.

Patch installed applications as soon as new updates become available.

Properly restrict the location of the software being used.

Use of sxstrace.exe on Windows as well as manual inspection of the manifests.

Require code signing and avoid using relative paths for resources.

Skills Required

[High] Trick the operating system in loading a malicious DLL instead of a legitimate DLL.