Extensions

Browser extensions, also known as plugins or add-ons, enhance the functionality of web browsers by adding new features or modifying existing ones. They can range from utility tools, ad blockers, and security plugins to customization themes. From a forensic perspective, analyzing extensions installed on a browser can reveal user preferences, potential sources of malware, and even evidence of specific user actions. Here's a closer look at how extensions are managed in popular browsers like Firefox, Google Chrome, and Microsoft Edge.

Firefox Extensions

• Firefox 4-25:

  • Extensions were managed in SQLite databases: extensions.sqlite and addons.sqlite.

• Firefox 26+:

  • The management of extensions transitioned to JSON files: addons.json and extensions.json.

  • Location: %USERPROFILE%\AppData\Roaming\Mozilla\Firefox\Profiles\<randomtext>.default\

  • The JSON format provides detailed information about each installed extension, including the name, installation source, installation time, last update, and plugin status.

Google Chrome and Microsoft Edge Extensions

• Location:

  • Chrome: %USERPROFILE%\AppData\Local\Google\Chrome\User Data\<Profile>\Extensions\<GUID>\<version>

  • Edge: %USERPROFILE%\AppData\Local\Microsoft\Edge\User Data\<Profile>\Extensions\<GUID>\<version>

• Extensions are stored in folders named after their unique GUID, with subfolders for each version.

• The creation time of the folder can hint at the installation time, but this may be influenced by syncing extensions across devices.

• The manifest.json file within each extension's folder contains essential details about the extension, including its name, URL, permissions, and version.

Analyzing Browser Extensions

1. Identify Installed Extensions: Navigate to the extensions directory for the browser and profile in question to list all installed extensions, or use this PowerShell Script.
2. Review Extension Metadata: Examine the manifest.json (Chrome/Edge) or addons.json/extensions.json (Firefox) files to gather information on the extensions, including their purpose, permissions, and version details.

3. Installation and Update Timestamps: Use file system metadata (creation and modification times) to determine when extensions were installed or updated. This can provide insights into user behavior or potential points of compromise.

4. Cross-Device Syncing Considerations: Be mindful that timestamps might reflect syncing actions rather than direct user installations, especially in environments where users log into their browser accounts on multiple devices.

5. Investigate Extension Preferences: For more in-depth analysis, review the preferences files where browsers may store additional data related to extension settings and states.

Forensic Implications

• User Behavior and Interests: The types of installed extensions can indicate user interests, such as productivity, privacy, or entertainment.

• Security Analysis: Malicious or compromised extensions can be vectors for malware, phishing, or data exfiltration. Identifying such extensions is crucial in cybersecurity investigations.

• Evidence of Actions: Some extensions might keep logs or data related to their functionality, which can serve as evidence of specific online actions or behaviors.