CVE-2012-4514 in Konqueror
Summary
by MITRE
rendering/render_replaced.cpp in Konqueror in KDE before 4.9.3 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted web page, related to "trying to reuse a frame with a null part."
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Analysis
by VulDB Data Team • 09/21/2024
The vulnerability identified as CVE-2012-4514 represents a critical denial of service flaw within the Konqueror web browser component of the KDE desktop environment. This issue specifically affects versions prior to 4.9.3 and stems from improper handling of frame reuse operations when dealing with null parts within the browser's rendering engine. The flaw occurs in the rendering/render_replaced.cpp file, which manages the display of replaced elements such as images, form controls, and other embedded objects that require special rendering behavior. When a malicious web page attempts to manipulate frame structures in a specific manner, the browser's rendering engine fails to properly validate frame state before attempting to reuse existing frames, leading to a NULL pointer dereference condition.
The technical exploitation of this vulnerability involves crafting a malicious web page that triggers a sequence of events causing the browser to attempt to reuse a frame that contains a null part reference. This particular scenario demonstrates a classic memory safety issue where the application fails to perform adequate null checks before dereferencing pointers. The flaw falls under the CWE-476 category of NULL Pointer Dereference, which is a well-documented vulnerability pattern where a program attempts to access memory through a pointer that has not been properly validated as non-null. The attack vector requires remote execution through web content delivery, making it particularly dangerous as users can be compromised simply by visiting a malicious website or clicking on a link that leads to such content.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to cause persistent browser instability and potentially create conditions for more sophisticated attacks. When the NULL pointer dereference occurs, it typically results in an immediate browser crash or hang, effectively rendering the affected browser unusable until manually restarted. This denial of service condition can be particularly problematic in enterprise environments where users rely heavily on web browsing capabilities for business operations. The vulnerability's remote nature means that exploitation can occur without any local user interaction beyond normal web browsing activities, making it an attractive target for attackers seeking to disrupt user productivity or create cover for more advanced attacks.
Mitigation strategies for CVE-2012-4514 primarily focus on immediate system updates and patches provided by the KDE development team. Organizations should prioritize upgrading to Konqueror version 4.9.3 or later, which includes the necessary code modifications to properly validate frame states before attempting reuse operations. Additionally, network administrators can implement web filtering solutions that block access to known malicious domains or employ content security policies that limit the execution of potentially harmful JavaScript code. The ATT&CK framework categorizes this vulnerability under the T1211 technique for exploitation of remote services, emphasizing the need for proper input validation and memory safety practices in browser development. Security monitoring should include detection of browser crash patterns and unusual frame reuse operations that may indicate exploitation attempts, while regular security assessments should verify that all browser components are running patched versions to prevent similar vulnerabilities from being exploited in the future.