CVE-2012-4515 in Konqueror
Summary
by MITRE
Use-after-free vulnerability in khtml/rendering/render_replaced.cpp in Konqueror in KDE 4.7.3, when the context menu is shown, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code by accessing an iframe when it is being updated.
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Analysis
by VulDB Data Team • 09/19/2024
The CVE-2012-4515 vulnerability represents a critical use-after-free flaw in the Konqueror web browser component of KDE 4.7.3 that specifically manifests during context menu operations involving iframe elements. This vulnerability falls under the CWE-416 category of use-after-free conditions, where memory that has been freed is subsequently accessed by the application. The flaw occurs within the khtml/rendering/render_replaced.cpp file, which handles the rendering of replaced elements such as iframes, making it a core component in the browser's rendering engine.
The technical exploitation of this vulnerability requires remote attackers to trigger a specific sequence of events involving the display of a context menu while an iframe is being updated. When Konqueror processes this scenario, the memory management system fails to properly handle the lifecycle of iframe objects, resulting in a freed memory pointer being accessed during the rendering process. This improper memory handling creates a condition where the application attempts to access memory that has already been deallocated, leading to unpredictable behavior. The vulnerability can manifest as either a denial of service through application crash or potentially more severe arbitrary code execution depending on the memory layout and exploitation circumstances.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a potential vector for remote code execution in the target system. When an attacker successfully triggers the use-after-free condition, the browser crashes and may potentially allow for memory corruption that could be leveraged to execute malicious code with the privileges of the compromised browser process. This risk is particularly concerning given that Konqueror was widely used as the default browser in KDE desktop environments, making it a potentially attractive target for attackers seeking to compromise desktop systems. The vulnerability's exploitation requires minimal user interaction beyond visiting a malicious webpage, making it particularly dangerous in phishing scenarios or when users browse untrusted websites.
Mitigation strategies for CVE-2012-4515 should prioritize immediate patching of affected KDE installations to version 4.8.0 or later, which contained the necessary memory management fixes. System administrators should also implement network-level protections such as web application firewalls and content filtering to prevent access to known malicious sites. Browser hardening techniques including sandboxing, memory protection mechanisms, and strict content security policies should be enabled to limit the potential impact of successful exploitation attempts. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping their software updated. The vulnerability demonstrates the critical importance of proper memory management in browser components and aligns with ATT&CK technique T1059.007 for command and script injection, as successful exploitation could lead to arbitrary code execution within the browser context. Organizations should also implement monitoring for unusual browser crash patterns or memory access violations that could indicate exploitation attempts.