CVE-2013-0787 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsEditor::IsPreformatted function in editor/libeditor/base/nsEditor.cpp in Mozilla Firefox before 19.0.2, Firefox ESR 17.x before 17.0.4, Thunderbird before 17.0.4, Thunderbird ESR 17.x before 17.0.4, and SeaMonkey before 2.16.1 allows remote attackers to execute arbitrary code via vectors involving an execCommand call.
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Analysis
by VulDB Data Team • 05/05/2021
The vulnerability identified as CVE-2013-0787 represents a critical use-after-free flaw within the Mozilla Firefox browser ecosystem and related applications including Thunderbird and SeaMonkey. This vulnerability resides in the nsEditor::IsPreformatted function located in the editor/libeditor/base/nsEditor.cpp file, which is part of the core editing components that handle text manipulation within these applications. The flaw manifests when processing certain execCommand calls, which are JavaScript methods used to execute editing commands within web content. The vulnerability affects multiple versions of the software, with specific remediation dates indicating that Firefox versions prior to 19.0.2, Firefox ESR 17.x versions prior to 17.0.4, Thunderbird versions prior to 17.0.4, Thunderbird ESR 17.x versions prior to 17.0.4, and SeaMonkey versions prior to 2.16.1 all remain susceptible to exploitation.
The technical nature of this vulnerability falls under the CWE-416 category, which specifically addresses use-after-free conditions where a program continues to reference memory after it has been freed, potentially leading to undefined behavior and exploitation opportunities. When an attacker crafts malicious web content that triggers an execCommand call in conjunction with the vulnerable IsPreformatted function, the application may attempt to access memory that has already been deallocated. This memory access violation can result in a range of malicious outcomes including arbitrary code execution, application crashes, or potentially more sophisticated attacks that leverage the freed memory for code injection purposes. The vulnerability's exploitation requires a remote attacker to deliver malicious content that will trigger the specific sequence of operations leading to the use-after-free condition.
The operational impact of CVE-2013-0787 extends beyond simple browser compromise, as it represents a significant threat to user security and system integrity. Attackers can leverage this vulnerability to execute arbitrary code on vulnerable systems with the privileges of the browser process, potentially leading to complete system compromise. The attack vector through execCommand calls makes this particularly dangerous because these commands are commonly used in web applications and can be easily embedded within malicious web pages. The vulnerability's presence in both Firefox and Thunderbird applications means that users across multiple Mozilla products are at risk, with the ESR (Extended Support Release) versions also affected, indicating that organizations using long-term support versions are not immune to this threat. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, where attackers can use JavaScript-based attacks to exploit browser vulnerabilities.
Mitigation strategies for this vulnerability require immediate patching of affected software versions to ensure that users are protected against exploitation attempts. Organizations should prioritize updating all affected Mozilla products including Firefox, Thunderbird, and SeaMonkey to their patched versions, with particular attention to ESR versions that may have extended support cycles. System administrators should implement security monitoring to detect potential exploitation attempts and consider implementing web content filtering solutions that can block known malicious JavaScript patterns. Additionally, users should be educated about the risks of visiting untrusted websites and opening email attachments that may contain malicious content designed to exploit this vulnerability. The vulnerability demonstrates the importance of regular security updates and proper memory management practices in software development, particularly for core components that handle user input and text processing operations. Security teams should also consider implementing sandboxing techniques and privilege separation to limit the potential impact if exploitation does occur, as the use-after-free condition could potentially be leveraged for more advanced persistent threats.