CVE-2008-1670 in KDE
Summary
by MITRE
Heap-based buffer overflow in the progressive PNG Image loader (decoders/pngloader.cpp) in KHTML in KDE 4.0.x up to 4.0.3 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted image.
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Analysis
by VulDB Data Team • 08/10/2019
The vulnerability identified as CVE-2008-1670 represents a critical heap-based buffer overflow within the progressive PNG image loader component of KHTML, which forms the core rendering engine for the KDE 4.0.x series desktop environment. This flaw exists specifically in the decoders/pngloader.cpp file and affects all versions of KDE 4.0.x up to and including 4.0.3. The vulnerability stems from insufficient input validation and memory management within the image decoding process, creating a condition where maliciously crafted PNG files can trigger unpredictable behavior in the affected software. The heap-based nature of this overflow indicates that the vulnerability occurs when the application attempts to write data beyond the allocated heap memory boundaries, potentially leading to memory corruption that can be exploited by remote attackers.
The technical exploitation of this vulnerability occurs when a user or application processes a specially crafted PNG image file through the KHTML rendering engine. During the progressive PNG decoding process, the application fails to properly validate the size parameters of image data segments, allowing an attacker to craft image files with malformed dimensions or data structures that exceed the allocated buffer space. This buffer overflow condition can result in stack corruption, memory pointer manipulation, and ultimately lead to application crashes or more severe exploitation outcomes. The vulnerability's classification as a heap-based buffer overflow aligns with CWE-121, which specifically addresses heap-based buffer overflow conditions that occur when insufficient bounds checking allows data to be written beyond the allocated heap memory region, making it susceptible to memory corruption attacks.
From an operational impact perspective, this vulnerability creates significant risks for users of KDE 4.0.x environments, particularly in scenarios where users might encounter untrusted image content through web browsing, email attachments, or file sharing platforms. The remote attack vector means that simply viewing or processing a maliciously crafted PNG image file can trigger the vulnerability without requiring any special user interaction beyond normal application usage. This makes the vulnerability particularly dangerous in web environments where users may inadvertently encounter malicious content, potentially leading to denial of service conditions that disrupt user productivity or, more critically, provide a foothold for arbitrary code execution. The vulnerability's potential for code execution stems from the memory corruption that can occur during heap overflow conditions, where attackers may be able to manipulate program execution flow through carefully crafted input data that overwrites critical memory locations.
The exploitation of this vulnerability aligns with several ATT&CK framework techniques, particularly those related to privilege escalation and execution through malicious file processing. The vulnerability can be leveraged as part of a broader attack chain where initial access is gained through web-based delivery mechanisms, followed by exploitation of the image processing component to achieve code execution. Security practitioners should note that this vulnerability demonstrates the critical importance of input validation in multimedia processing components, as image decoders are frequently targeted by attackers due to their complex parsing requirements and the variety of potential input formats they must handle. The vulnerability also highlights the need for regular security updates and patch management processes, as the affected KDE versions were released prior to comprehensive security hardening practices that would have prevented such buffer overflow conditions from existing in the codebase. Organizations should prioritize immediate patching of affected systems and implement additional security controls such as image validation at network boundaries or application sandboxing to mitigate the risk of exploitation in environments where patching may be delayed or difficult to implement.