Malicious Code Injected via Google Chrome Extension Highlights App Risks

Google has removed a Chrome plugin used by approximately 2 million users after reports that the browser extension had been compromised and installed potentially malicious code and tracking software on users' systems.

The Great Suspender utility for Chrome has a very simple task—reduce the memory consumed by the browser through shutting down tab processes that are old, removing their content from memory. Yet, the original maintainer of the open-source project sold the code to an unknown group, who changed the functionality of the plugin and installed updated code on users' systems without notification and without publishing the code to the plugin's repository on GitHub, according to some reports.

This recent Chrome plugin incident, along with SolarWinds and other software compromise, highlight how attackers are focusing on software ecosystems outside the main application stores such as the Apple Store and Google Play store, says Vinnie Liu, the CEO of Bishop Fox.

"The secure development lifecycle has for 15 years been focused on preventing the inadvertent introduction of vulnerabilities by developers, and not against identifying and preventing the purposeful insertion of malicious code or behavior into an existing application," he says. "Developers are unprepared for this. Most enterprise security programs are unprepared for this." 

Neither Google - which removed the software on Feb. 4 - nor the original developer of the software, Dean Oemcke, had responded to requests for comment as of this posting.

Application security firms have warned that open-source components and third-party software should be vetted for vulnerabilities and, increasingly, as a supply-chain issue. The cyber espionage attack that infected customers of SolarWinds by adding code to the software, and the spread of the NotPetya worm through the compromise of a Ukrainian accounting software update, both highlight the dangers of third-party security failures.

"We should use systematic detection—like publicly verifiable software bills of material—of software, so we can check, detect, and track changes," says Stefan Frei, security officer at SDX Security and a lecturer on application security at ETH Zurich, a large public university in Switzerland. "Unexpected, or large changes in a popular upstream app, plugin, [or] project would trigger closer investigation to understand the type of changes introduced."

Unanswered Questions

The full story behind the changes in the Great Suspender remains unclear. In June 2020, the maintainer of the open-source project reportedly sold the project to an unidentified group. Three months later, the extension available on the Google Chrome and Microsoft Edge stores appeared to contain questionable code. Microsoft removed the Edge extension in November, but Google continued to offer the extension in its store until last Thursday.

Information on the functionality of the malicious code also is still hard to find. An analysis of the situation posted by Callum McConnell in November noted that the latest versions available in the stores appeared to load intentionally-hidden data. 

"Because the malicious code loaded from a server by the extension ... was heavily obfuscated, it is hard to say what may have been compromised," the analysis stated. "However, those who did manage to conduct [a] successful analysis of the code reported no password-stealing functionality in the copies that were archived."

Companies should track software bill-of-materials and ensure that software on users' systems is analyzed for security issues - and any changes to the code is tracked. Software component analysis (SCA), which tracks the state of open-source components and other libraries, has quickly become important for software makers' secure development lifecycle (SDL) initiatives.

A broader initiative may also be necessary, involving an industry associate or government agency to run such a service, says SDX Security's Frei.

"Maybe we need a government or industry to run such a shop ... for the common good," he says. "Coupled with code signing (and) rules that [code] certificates get revoked if ownership is changes without proper process [or] notice."

Users and companies should expect attackers to continue to create campaigns that focus on smaller ecosystems. With Apple, Google, and Microsoft investing more money into software security, using popular software with less-robust security measures will be more common, says Bishop Fox's Liu.

"The attackers are going to adapt by moving into these other areas that have not gotten the same security scrutiny," he says. "There are cheaper ways to get what they want, so we are seeing adversaries adapt to those changing economics."