SquareX Discloses Architectural Limitations of Browser DevTools in Debugging Malicious Extensions
The Illusion of Security: “Verified” Labels Offer False Reassurance
Palo Alto, Calif. – July 29 – Despite the expanding use of browser extensions, the majority of enterprises and individuals still rely heavily on labels such as “Verified” and “Chrome Featured” provided by extension stores as indicators of security. However, the recent Geco Colorpick case clearly illustrates that these certifications offer little more than a false sense of security. Specifically, Koi Research1 recently disclosed 18 malicious extensions that distributed spyware to 2.3 million users—and notably, most of these extensions carried the supposedly trustworthy “Verified” status.
The DevTools Dilemma: Why Runtime Analysis Falls Short
SquareX researchers disclosed the technological reason behind this vulnerability, highlighting an architectural flaw in Browser DevTools that prevents browser vendors and enterprises from performing the thorough security analysis many enterprises expect. “Thousands of extension updates and submissions occur daily, making it impossible for browser vendors to monitor and assess an extension’s security posture at runtime,” says Nishant Sharma, Head of Security Research at SquareX. “This limitation exists because existing DevTools were designed to inspect web pages.” Extensions are complex beasts that can behave dynamically, work across multiple tabs, and have “superpowers” that allow them to easily bypass detection via rudimentary Browser DevTool telemetry.” In other words, even if browser vendors weren’t drowning in endless extension submissions, today’s Browser DevTools have architectural flaws that would still let plenty of malicious extensions slip through security checks.
Old Tools, New Problems: DevTools Weren’t Built for Extensions
Browser vendors introduced DevTools in the late 2000s, long before extensions became widespread. They designed these tools to help users and web developers debug websites and inspect web page elements. However, browser extensions possess unique capabilities, such as modifying web pages, taking screenshots, and injecting scripts into multiple pages, which DevTools can’t easily monitor or attribute. For example, an extension may make a network request through a web page by injecting a script into the page. With Browser DevTools, there is no way to differentiate network requests made by the web page itself and those made by an extension.
The Sandbox Solution: AI Agents and Modified Browsers to the Rescue
Detailed in the technical blog, SquareX’s researchers propose a novel approach that uses the combination of a modified browser and Browser AI Agents to plug this gap. The modified browser exposes critical telemetry required to understand an extension’s true behavior, while the Browser AI Agent simulates different user personas to incite various extension behaviors at runtime for monitoring and security analysis. This enables dynamic analysis of the extension and uncovers various “hidden” extension behaviors that only trigger based on time, specific user actions, or device environments. Named the Extension Monitoring Sandbox, the research details the necessary modifications required for the modified browser.
Time for Action: Bridging the Gap in Browser Extension Security
The revelation of Browser DevTools’ architectural limitations exposes a fundamental security gap that has led to the compromise of millions of users. As browser extensions become a core part of the enterprise workflow, it is critical for enterprises to move from superficial labels to solutions specifically designed to tackle extension security. It is absolutely critical for browser vendors, enterprises, and security vendors to work closely together in tackling what has become one of the fastest emerging threat vectors.
Free August Audit: Assessing Extension Risk the Right Way
This August, SquareX is offering a free enterprise-wide extension audit in August. The audit involves conducting an extensive audit of all extensions installed across the organization using all three components of the SquareX Extension Analysis Framework – metadata analysis, static code analysis, and dynamic analysis with the Extension Monitoring Sandbox – providing a full analysis of the organization’s extension risk exposure and a risk score for each extension.
About SquareX
SquareX’s browser extension transforms any browser on any device into an enterprise-grade secure browser. SquareX’s industry-first Browser Detection and Response (BDR) solution empowers organizations to proactively detect, mitigate, and threat-hunt client-side web attacks, including malicious browser extensions, advanced spearphishing, browser-native ransomware, GenAI data loss prevention, and more.
Unlike legacy security approaches and cumbersome enterprise browsers, SquareX seamlessly integrates with users’ existing consumer browsers, ensuring enhanced security without compromising user experience or productivity. By delivering unparalleled visibility and control directly within the browser, SquareX enables security leaders to reduce their attack surface, gain actionable intelligence, and strengthen their enterprise cybersecurity posture against the newest threat vector – the browser.
Find out more at www.sqrx.com
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