Cybersecurity researchers have recently identified a new dangerous infostealer malware called “ZeroCrumb.” This sophisticated malware was recently being distributed through various public GitHub code repositories. ZeroCrumb specifically targets browser cookies from very popular web browsers used by many. These targeted browsers include Google Chrome Brave and also the Microsoft Edge browser. This enables attackers to steal users’ sensitive authentication data without triggering User Account Control (UAC) alerts. User Account Control alerts typically warn users of potentially suspicious system activity. The malware employs advanced techniques to successfully extract users’ valuable encrypted browser credentials. This could allow threat actors to hijack active web sessions and gain account access.
ZeroCrumb malware operates by exploiting the browser’s own internal complex security architecture. It specifically targets the encrypted storage mechanisms used by browsers to protect cookie data. Unlike many conventional cookie stealers it does not require any administrative system privileges. This new malware implements a novel approach that circumvents standard operating system security protections. This makes it particularly dangerous for both corporate environments and also individual users alike. ZeroCrumb can easily extract valuable authentication tokens from any of the compromised computer systems. This could potentially lead to unauthorized account takeovers across multiple online services simultaneously. KrakenLabs security researchers first identified this emerging threat through observing unusual data exfiltration. Their analysis revealed ZeroCrumb represents a significant evolution in modern cookie-stealing software techniques.
ZeroCrumb expertly bypasses the Chrome Elevation Service using a technique called Transacted Hollowing.
This advanced technique effectively allows the malware to impersonate a legitimate Chrome browser instance. This crucial impersonation enables the malware to interface with the IElevator COM system interface. It then uses this particular interface to successfully decrypt the browser’s App Bound Key. This decrypted App Bound Key is subsequently used to access users’ encrypted browser cookies. The malware’s implementation cleverly utilizes named pipes allowing programs with Windows API access to connect. This allows other processes to connect to the ZeroCrumb pipe and extract the key. ZeroCrumb can also be compiled as a DLL embedding the key dumper in its resources. This specific approach makes its detection particularly challenging for most existing security tools.
The widespread adoption of browser-based applications makes this new ZeroCrumb threat particularly concerning.
Many critical business and important personal use tasks are now done via web browsers. Compromised browser cookies can quickly provide attackers with very immediate unauthorized system access. This includes easy access to private email accounts and also sensitive cloud storage services. Important financial services and valuable corporate data resources are also put at high risk. Attackers gain this deep access without needing to crack any user account passwords directly. They also do not usually need to bypass existing multi-factor authentication security measures. ZeroCrumb effectively mimics legitimate browser processes while performing its many malicious background activities. This very stealthy behavior further complicates detection efforts by installed security software.
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