CVE-2012-4212 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the XPCWrappedNative::Mark function in Mozilla Firefox before 17.0, Thunderbird before 17.0, and SeaMonkey before 2.14 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via unspecified vectors.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/31/2018
The CVE-2012-4212 vulnerability represents a critical use-after-free flaw within the XPCWrappedNative::Mark function of Mozilla's browser applications. This vulnerability affects Firefox versions prior to 17.0, Thunderbird versions prior to 17.0, and SeaMonkey versions prior to 2.14, creating a significant security risk that could be exploited by remote attackers. The flaw resides in the JavaScript engine's garbage collection mechanism where memory that has been freed is still being referenced, creating a dangerous condition that can be leveraged for code execution.
The technical implementation of this vulnerability occurs within the XPCWrappedNative::Mark function which is responsible for marking JavaScript objects for garbage collection in Mozilla's XPC (Cross-Platform Component) system. When processing certain JavaScript objects, the function fails to properly manage memory references, allowing an attacker to manipulate the object lifecycle and force the system to access freed memory locations. This use-after-free condition specifically manifests when the XPCWrappedNative objects are being marked for collection while other code paths are still accessing them, creating a race condition that can be exploited through carefully crafted malicious web content.
The operational impact of this vulnerability extends beyond simple denial of service to include full remote code execution capabilities. Attackers can leverage this heap memory corruption to overwrite critical memory structures, potentially redirecting execution flow to malicious code injected into the heap. The vulnerability's remote exploitability means that simply visiting a malicious website could compromise a user's system without any user interaction beyond normal browsing behavior. This makes it particularly dangerous in the context of modern web browsing where users frequently encounter untrusted content.
The exploitation of CVE-2012-4212 aligns with several attack patterns documented in the ATT&CK framework, particularly those involving memory corruption vulnerabilities and privilege escalation techniques. The vulnerability falls under CWE-416 which specifically addresses use-after-free conditions, making it a prime target for exploit development. The attack surface is broad since it affects multiple Mozilla products and can be triggered through various web-based vectors including JavaScript execution, DOM manipulation, and cross-origin resource handling. Security researchers have noted that this vulnerability represents a classic heap-based buffer overflow scenario that can be amplified through heap spraying techniques.
Mitigation strategies for CVE-2012-4212 require immediate patching of affected software versions, as the vulnerability cannot be effectively addressed through configuration changes or network filtering. Organizations should prioritize updating to Firefox 17.0, Thunderbird 17.0, and SeaMonkey 2.14 or later versions where the memory management issues have been resolved through proper reference counting and object lifecycle management. Additional defensive measures include implementing content security policies, disabling unnecessary JavaScript features, and deploying web application firewalls that can detect and block known exploit patterns. The vulnerability demonstrates the critical importance of proper memory management in complex software systems and highlights the need for comprehensive code reviews focusing on object lifetime management and garbage collection mechanisms.