CAPEC Definitions / CAPEC-698
CAPEC-698: Install Malicious Extension
An adversary directly installs or tricks a user into installing a malicious extension into existing trusted software, with the goal of achieving a variety of negative technical impacts.
Extended Description
Many software applications allow users to install third-party software extensions/plugins that provide additional features and functionality. Adversaries can take advantage of this behavior to install malware on a system with relative ease. This may require the adversary compromising a system and then installing the malicious extension themself. An alternate approach entails masquerading the malicious extension as a legitimate extension. The adversary then convinces users to install the malicious component, via means such as social engineering, or simply waits for victims to unknowingly install the malware on their systems. Once the malicious extension has been installed, the adversary can achieve a variety of negative technical impacts such as obtaining sensitive information, executing unauthorized commands, observing/modifying network traffic, and more.
Mitigations
Only install extensions/plugins from official/verifiable sources.
Confirm extensions/plugins are legitimate and not malware masquerading as a legitimate extension/plugin.
Ensure the underlying software leveraging the extension/plugin (including operating systems) is up-to-date.
Implement an extension/plugin allow list, based on the given security policy.
If applicable, confirm extensions/plugins are properly signed by the official developers.
For web browsers, close sessions when finished to prevent malicious extensions/plugins from executing the the background.
Relationships with other CAPECs
CAPEC-542: Targeted Malware
Prerequisites
The adversary must craft malware based on the type of software and system(s) they intend to exploit.
If the adversary intends to install the malicious extension themself, they must first compromise the target machine via some other means.
