CVE-2013-1681 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsContentUtils::RemoveScriptBlocker function in Mozilla Firefox before 21.0, Firefox ESR 17.x before 17.0.6, Thunderbird before 17.0.6, and Thunderbird ESR 17.x before 17.0.6 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via unspecified vectors.
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Analysis
by VulDB Data Team • 05/11/2021
The CVE-2013-1681 vulnerability represents a critical use-after-free flaw within Mozilla Firefox and Thunderbird browser applications that existed prior to specific version releases. This vulnerability resides in the nsContentUtils::RemoveScriptBlocker function, which is responsible for managing script execution blocking mechanisms within the browser's rendering engine. The flaw manifests when the application attempts to access memory that has already been freed, creating a scenario where malicious actors can manipulate the heap memory structure to execute arbitrary code or induce system crashes.
This particular vulnerability falls under the CWE-416 category, which specifically addresses use-after-free conditions in software applications. The technical implementation involves improper memory management where the RemoveScriptBlocker function fails to properly handle reference counting or object lifecycle management during script processing operations. When the browser processes certain web content that triggers script blocking mechanisms, the function may release memory associated with script objects while other code paths still maintain references to those objects, creating a window where attackers can exploit the dangling pointer.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass full remote code execution capabilities. Attackers can craft malicious web pages that, when loaded in vulnerable browsers, trigger the use-after-free condition in heap memory. This exploitation allows adversaries to potentially execute arbitrary code with the privileges of the browser process, leading to complete system compromise. The vulnerability's remote exploitability means that users need only visit a malicious website to be compromised, making it particularly dangerous in real-world scenarios. The heap corruption aspect also means that the attack can cause unpredictable behavior including application crashes, data corruption, or system instability that can be leveraged for more sophisticated attacks.
Mitigation strategies for this vulnerability require immediate patching of affected software versions to the recommended secure releases including Firefox 21.0, Thunderbird 17.0.6, and their respective ESR versions. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Network-based mitigations such as web application firewalls and content filtering systems can provide additional protection layers, though these should not replace proper patching. Security monitoring should include detection of suspicious web traffic patterns and unusual memory usage behaviors that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper memory management practices in browser security and highlights the need for regular security audits and code reviews focusing on object lifecycle management and reference counting mechanisms. Organizations should also consider implementing browser hardening techniques and privilege separation measures to limit the potential impact of successful exploitation attempts.