CAPEC-641 DLL Side-Loading – Attack Pattern Analysis

CAPEC-641 Metadata

Likelihood of Attack

Low

Typical Severity

High

Overview

Summary

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.

Potential Solutions / 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.

Related Weaknesses (CWE)

CWE ID	Description
CWE-706	Use of Incorrectly-Resolved Name or Reference

Related CAPECs

CAPEC ID	Description
CAPEC-159	An adversary exploits a weakness in the way an application searches for external libraries to manipulate the execution flow to point to an adversary supplied library or code base. This pattern of attack allows the adversary to compromise the application or server via the execution of unauthorized code. An application typically makes calls to functions that are a part of libraries external to the application. These libraries may be part of the operating system or they may be third party libraries. If an adversary can redirect an application's attempts to access these libraries to other libraries that the adversary supplies, the adversary will be able to force the targeted application to execute arbitrary code. This is especially dangerous if the targeted application has enhanced privileges. Access can be redirected through a number of techniques, including the use of symbolic links, search path modification, and relative path manipulation.

CAPEC ID

Description

CAPEC-159

An adversary exploits a weakness in the way an application searches for external libraries to manipulate the execution flow to point to an adversary supplied library or code base. This pattern of attack allows the adversary to compromise the application or server via the execution of unauthorized code. An application typically makes calls to functions that are a part of libraries external to the application. These libraries may be part of the operating system or they may be third party libraries. If an adversary can redirect an application's attempts to access these libraries to other libraries that the adversary supplies, the adversary will be able to force the targeted application to execute arbitrary code. This is especially dangerous if the targeted application has enhanced privileges. Access can be redirected through a number of techniques, including the use of symbolic links, search path modification, and relative path manipulation.

Taxonomy Mappings

Taxonomy: ATTACK

Entry ID	Entry Name
1574.002	Hijack Execution Flow:DLL Side-Loading

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