CVE-2017-6311 in gdk-pixbuf
Summary
by MITRE
gdk-pixbuf-thumbnailer.c in gdk-pixbuf allows context-dependent attackers to cause a denial of service (NULL pointer dereference and application crash) via vectors related to printing an error message.
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Analysis
by VulDB Data Team • 09/05/2020
The vulnerability identified as CVE-2017-6311 resides within the gdk-pixbuf library's thumbnailer component, specifically in the gdk-pixbuf-thumbnailer.c file. This issue represents a classic null pointer dereference flaw that can be exploited by context-dependent attackers to trigger application crashes and subsequent denial of service conditions. The vulnerability manifests when the library attempts to process certain image files or malformed input during the thumbnail generation process, particularly when error handling routines are invoked.
The technical flaw stems from inadequate input validation and error handling within the gdk-pixbuf library's image processing pipeline. When encountering specific malformed image data or edge cases during thumbnail generation, the code fails to properly check for null pointers before dereferencing them during error message printing operations. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions, and represents a fundamental weakness in defensive programming practices. The flaw demonstrates poor error handling mechanisms that do not adequately protect against unexpected input conditions.
From an operational impact perspective, this vulnerability can be exploited to cause significant disruption in applications that rely on gdk-pixbuf for image processing and thumbnail generation. Systems using this library for file browsing, image management, or document preview functions become vulnerable to denial of service attacks that can crash applications or render entire interfaces unusable. The attack vector is context-dependent meaning that exploitation requires specific conditions related to the input being processed, but once triggered, the impact is immediate and observable through application crashes or unresponsive behavior.
The vulnerability's exploitation aligns with ATT&CK technique T1499.004 which covers network denial of service attacks through application or system crashes. Attackers can leverage this weakness by presenting specially crafted image files to applications that utilize gdk-pixbuf for thumbnail generation, potentially causing cascading failures in desktop environments, file managers, or web applications. The impact extends beyond individual applications to potentially affect entire desktop environments or server applications that depend on consistent image processing capabilities.
Mitigation strategies should focus on updating to patched versions of the gdk-pixbuf library where the null pointer dereference has been addressed through proper input validation and error handling. System administrators should implement comprehensive patch management procedures to ensure all affected applications using this library are updated promptly. Additionally, input sanitization measures should be implemented at application layers that consume gdk-pixbuf functionality, including validation of image file formats and implementation of proper exception handling to prevent crashes from propagating. The vulnerability serves as a reminder of the critical importance of robust error handling in image processing libraries and the potential for seemingly minor flaws to cause significant operational disruptions.