Protecting Against Browser Extension Attacks with Modern Application Control

The recent compromise of Chrome extensions, including one published by the data protection company Cyberhaven, highlights the growing threat of malicious browser extension exploitation.

Hackers were able to push a compromised version of Cyberhaven’s Chrome extension, potentially stealing sensitive user data. As of the date of this writing, some 25+ additional extensions were also affected, suggesting this attack was part of a broader, opportunistic effort to compromise as many systems as possible. These incidents underscore the urgent need for proactive security measures like Airlock Digital’s modern application control, which can prevent such breaches before they occur. 

 

The Threat:  Browser Extensions 

Browser extensions have become a critical tool for organizations, enhancing functionality and enabling workflows in applications like artificial intelligence tools, VPNs, and web-based monitoring platforms. However, their access to sensitive data and elevated privileges make them a prime target for attackers. As seen in the CyberHaven incident, hackers can compromise extensions at the source or distribution level, injecting malicious code that steals credentials, user IDs, and other critical information. 

In Cyberhaven’s case, the Chrome extension was used to monitor and secure client data flowing through web-based applications. Once compromised, it became a tool for attackers to exfiltrate data from Cyberhaven's users, amplifying the attack’s impact. Reactive security measures, such as resetting passwords, clearing tokens, and ending sessions after an incident are vital, but insufficient to prevent these types of breaches. 

 

How Modern Application Control Mitigates Risks 

Enforcing a "Deny by Default" Model 

The best application control solutions operate on the principle of "Deny by Default," ensuring that only explicitly trusted applications and browser extensions are allowed to execute. For organizations like Cyberhaven, this approach would: 

    • Block unauthorized extensions, including compromised versions of legitimate tools. 
    • Automatically prevent the execution of browser extensions modified with malicious code, as their integrity would fail validation against the solution’s allowlist. 

By enforcing strict control at the application level, effective application control could have prevented the malicious versions of these extensions from running.

 

Protecting Sensitive Applications 

In addition to securing browser extensions, effective application control protects applications that handle sensitive client data. For organizations using tools to monitor and secure web-based workflows, application control ensures that: 

    • Only approved software is used to process sensitive data. 
    • Attempts to introduce or execute malicious tools within the organization are proactively blocked. 

This would minimize the risk of attackers leveraging compromised extensions to exfiltrate client data, as occurred in this attack. 

 

Addressing Supply Chain Risks 

The attackers in this incident targeted extensions during their development or distribution, highlighting the risks of supply chain attacks.  The integrity testing and validation conducted by  the best application control solutions mitigates these risks: 

    • Modified or subverted versions of software are rejected, preventing execution even if they are mistakenly distributed. 
    • Organizations retain control over which updates are approved and deployed across their environments. 

 

Reducing the Impact of Opportunistic Attacks 

As this incident demonstrates, many attacks are not specifically targeted but are opportunistic in nature. By compromising a range of extensions, hackers aim to gather as much data as possible from diverse victims. Well-designed application control solutions like Airlock Digital reduce the attack surface for opportunistic threats by: 

    • Blocking all unapproved or unknown applications by default. 
    • Providing real-time insights into execution attempts, enabling faster incident detection. 

 

Streamlining Incident Response 

Proven application control solutions also support organizations in post-incident scenarios by: 

    • Offering centralized management to quickly revoke trust for compromised extensions and prevent further execution. 
    • Generating detailed audit logs that allow organizations to identify and isolate endpoints impacted by unauthorized software attempts. 

 

Lessons from the CyberHaven Incident 

This recent attack highlights the vulnerability of browser extensions, particularly those used in sensitive workflows like data protection or AI tools. The attackers exploited their elevated privileges to harvest sensitive information, leveraging compromised extensions as a vector for mass data collection. 

The incident underscores the need for organizations to adopt proactive, preventative endpoint defenses. Reactive measures - such as antivirus or endpoint detection and response (EDR) - may fail to block these threats in real time, as they often rely on detecting known signatures or behavior patterns after execution. 

 

The Time for Proactive Endpoint Protection 

As browser extensions become increasingly critical to organizational workflows, their exploitation represents a growing threat. Application Control is now essential to defending against these risks. By enforcing a "Deny by Default" model and ensuring the integrity of all executed applications, application control provides a strong defense against both targeted and opportunistic attacks.  

 

For more information about how Airlock Digital can safeguard your organization, schedule a demo today. 

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