CVE-2011-0057 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the Web Workers implementation in Mozilla Firefox before 3.5.17 and 3.6.x before 3.6.14, and SeaMonkey before 2.0.12, allows remote attackers to execute arbitrary code via vectors related to a JavaScript Worker and garbage collection.
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Analysis
by VulDB Data Team • 10/18/2021
The vulnerability identified as CVE-2011-0057 represents a critical use-after-free flaw within the Web Workers implementation of Mozilla Firefox and SeaMonkey browsers. This issue affects versions prior to Firefox 3.5.17 and 3.6.x before 3.6.14, as well as SeaMonkey before 2.0.12, creating a significant security risk that could be exploited by remote attackers to execute arbitrary code on affected systems. The vulnerability specifically targets the browser's handling of JavaScript Worker objects during garbage collection processes, which forms part of the browser's multi-threading capabilities for background processing tasks.
The technical nature of this flaw stems from improper memory management within the Web Workers subsystem where a JavaScript Worker object is freed from memory but continues to be referenced or accessed by other components of the browser's execution environment. When the garbage collector attempts to reclaim memory occupied by a Worker object that has already been destroyed, the system may allow subsequent operations to access this freed memory location, creating a use-after-free condition. This memory corruption scenario occurs because the browser fails to properly track the lifecycle of Worker objects and their associated memory allocations during the garbage collection cycle. The vulnerability operates at the intersection of memory management and concurrency control, where the timing of object destruction and memory reclamation creates opportunities for exploitation.
The operational impact of this vulnerability extends beyond simple browser compromise, as successful exploitation could lead to complete system control by remote attackers. Attackers can craft malicious web pages that trigger the specific sequence of events leading to the use-after-free condition, potentially executing arbitrary code with the privileges of the browser process. This capability enables various attack vectors including information disclosure, privilege escalation, and persistent system compromise. The vulnerability affects web workers specifically when they interact with garbage collection mechanisms, making it particularly dangerous in environments where users browse untrusted websites or encounter malicious web content. The attack surface is broad since Web Workers are commonly used in modern web applications, increasing the likelihood of exploitation in real-world scenarios.
Mitigation strategies for CVE-2011-0057 focus primarily on immediate version upgrades to patched browser releases, with users urged to update Firefox to version 3.5.17 or later, 3.6.14 or later, and SeaMonkey to 2.0.12 or later. Security administrators should implement comprehensive patch management protocols to ensure all affected systems receive updates promptly. Additional protective measures include browser hardening configurations that restrict Web Workers usage, implementing content security policies that limit cross-origin resource sharing, and deploying network-based intrusion detection systems to monitor for exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-416, which addresses use-after-free conditions in software implementations, and represents a significant concern for organizations following security frameworks such as NIST SP 800-53 controls for system security and vulnerability management. The ATT&CK framework categorizes this vulnerability under T1059.007 for scripting languages and T1203 for Exploitation for Client Execution, highlighting the multi-layered attack approach required to successfully exploit such memory corruption vulnerabilities in modern browser environments.