Mastering Browser Extensions: Key Strategies for Effective Analysis and Threat Prevention
Background: In today’s digital landscape, browser extensions are immensely popular for automating tasks and enhancing productivity. Millions of users rely on these tools to streamline their workflows. However, this widespread adoption also presents a significant risk: it provides a potential avenue for threat actors to distribute malicious code to a broad audience.
Attack flow: Threat actors have several methods to exploit browser extensions for their gain:
- Exploiting Over-Permission: They might use their own solutions to request excessive permissions from users, allowing them to gain unauthorized access and control.
- Hijacking Abandoned Domains: They could identify and exploit domains associated with outdated or abandoned extensions by purchasing a similar domain and redirecting traffic or compromising the extension.
- Compromising Developer Accounts: They may target and breach extension developer accounts to alter the source code, inserting malicious elements or vulnerabilities.
Detection and Analyze strategies: Before deep dive into analyze need to understand the structure of extensions .
Manifest.json : Responsible for getting information related to permission
Background.json: Responsible for injecting additional JS listeners into browser
_metadata or META_INF: Contains checksums for the included files to ensure their integrity. This helps mitigate the risk that a threat actor could download the original extension, modify its contents, and then distribute the altered version to end users.
Check permissions - Over-permissioning in browser extensions can pose significant risks. Some permissions may be unnecessary and not aligned with the functionality described by the developer. For example, one permission allows an extension to access all URLs in the browser, which could expose users to privacy and security risks if not properly justified.
Check Source Code Both Manually and Automatically: JavaScript code can be either obfuscated or non-obfuscated, and both can pose risks such as data exfiltration. To effectively detect these threats and ensure code security, it is essential to implement a combination of manual and automated analysis methods.
Check If Vendor Complained: If an extension handles sensitive data, it is crucial to verify with the vendor or platform if there have been any reported issues or complaints. Understanding these concerns can help mitigate potential risks and enhance the security of the extension.
Check Individual Contributor Emails: If the extension maintainer is an individual contributor, verify whether their email account has been compromised. This can help identify potential security risks and ensure that the extension's integrity is not at risk due to unauthorized access or manipulation.
Mitigation/Detection strategies:
- Implement a managed browser strategy that restricts users from installing any extensions without prior review and approval from designated specialists. This approach ensures that extensions are vetted for security and compliance before being added to the browser environment.
- To enhance security and streamline the process of detecting potential threats in browser extensions, you can automate detection using the Crxcavator API.
Happy Hunting - Jok3r