CVE-2013-0766 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the ~nsHTMLEditRules implementation in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and 17.x before 17.0.1, Thunderbird before 17.0.2, Thunderbird ESR 10.x before 10.0.12 and 17.x before 17.0.1, and SeaMonkey before 2.15 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 • 04/20/2021
The CVE-2013-0766 vulnerability represents a critical use-after-free flaw within the nsHTMLEditRules implementation of Mozilla's browser and email applications. This vulnerability specifically affects Firefox versions prior to 18.0, Firefox ESR 10.x versions before 10.0.12 and 17.x versions before 17.0.1, Thunderbird versions prior to 17.0.2, Thunderbird ESR 10.x versions before 10.0.12 and 17.x versions before 17.0.1, and SeaMonkey versions prior to 2.15. The flaw resides in the HTML editing rules engine that handles content manipulation within the browser's rich text editing capabilities, making it particularly dangerous as it can be triggered through web page content manipulation.
The technical nature of this vulnerability stems from improper memory management within the nsHTMLEditRules class, where freed memory blocks are still being accessed or referenced after their intended use has concluded. This use-after-free condition creates a heap memory corruption scenario that can be exploited by remote attackers to execute arbitrary code on affected systems or cause denial of service conditions. The vulnerability manifests when the editing rules engine processes HTML content that triggers specific memory deallocation sequences followed by subsequent access patterns that reuse the freed memory space, potentially allowing attackers to inject malicious code into the browser process memory space.
From an operational perspective, this vulnerability presents a significant risk to users of affected Mozilla products, as it can be exploited through web-based attacks without requiring user interaction beyond visiting a malicious webpage. The exploitation potential spans across multiple Mozilla applications, including the primary web browser Firefox, the email client Thunderbird, and the integrated browser suite SeaMonkey, amplifying the attack surface considerably. Attackers can leverage this flaw to gain remote code execution capabilities, potentially leading to full system compromise, data theft, or persistent backdoor installation on vulnerable systems. The heap corruption nature of the vulnerability also means that the attack surface extends beyond simple code execution to include potential privilege escalation and system stability compromise.
Security mitigations for CVE-2013-0766 primarily focus on immediate application updates to patched versions, as this vulnerability was addressed through memory management fixes in the affected software releases. Organizations should prioritize patch deployment across all affected Mozilla products, particularly in enterprise environments where multiple users may be exposed to web-based threats. Additionally, implementing network-based security controls such as web application firewalls and content filtering solutions can provide additional layers of protection against exploitation attempts. The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions, and can be mapped to ATT&CK technique T1059.007 for remote code execution through browser exploits, highlighting the need for comprehensive endpoint protection strategies. Regular security assessments and vulnerability scanning should be conducted to identify any remaining unpatched systems within the organization's infrastructure.