CVE-2020-20739 in libvips
Summary
by MITRE • 11/21/2020
im_vips2dz in /libvips/libvips/deprecated/im_vips2dz.c in libvips before 8.8.2 has an uninitialized variable which may cause the leakage of remote server path or stack address.
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Analysis
by VulDB Data Team • 12/09/2020
The vulnerability identified as CVE-2020-20739 resides within the libvips image processing library, specifically in the deprecated im_vips2dz.c module. This issue affects versions prior to 8.8.2 and represents a critical security flaw that could potentially expose sensitive information from remote servers. The vulnerability manifests through an uninitialized variable that can lead to information disclosure, creating opportunities for attackers to gather server paths or stack addresses that should remain confidential. Such information leakage can significantly aid threat actors in planning more sophisticated attacks against the affected systems.
The technical flaw occurs within the im_vips2dz function which is responsible for converting vips image formats to deep zoom formats. When processing certain image inputs, the code fails to properly initialize a variable before using its value, creating a scenario where uninitialized memory contents are inadvertently exposed. This uninitialized variable behavior can result in the leakage of stack memory addresses or file system paths that were previously allocated but never explicitly set to known values. The vulnerability falls under the category of information disclosure issues that can be classified as CWE-457: Use of Uninitialized Variable, which is a well-documented weakness in software development practices. The improper handling of uninitialized variables represents a fundamental programming error that can have severe security implications when the uninitialized memory contains sensitive data.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked server paths and stack addresses can provide attackers with crucial reconnaissance data for further exploitation attempts. An attacker who successfully exploits this vulnerability could gain insights into the server's directory structure, potentially identifying sensitive file locations or system internals that could be leveraged in subsequent attacks. This information leakage could be particularly damaging in environments where the affected libvips library is used in web applications or server-side processing systems, as it provides attackers with additional attack surface information that could be combined with other vulnerabilities to achieve more significant compromises. The vulnerability's presence in a deprecated module also raises concerns about the overall security posture of systems that continue to rely on outdated components.
The recommended mitigation strategy involves upgrading to libvips version 8.8.2 or later, which contains the necessary fixes to address the uninitialized variable issue. Organizations should conduct immediate assessments to identify systems running vulnerable versions of libvips and prioritize the upgrade process. Additionally, implementing proper input validation and sanitization measures can help reduce the attack surface, while monitoring systems should be configured to detect any suspicious activity that might indicate exploitation attempts. The vulnerability's classification aligns with ATT&CK technique T1082: System Information Discovery, as it enables adversaries to gather system information that could be used for further reconnaissance. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of information disclosure vulnerabilities, while maintaining regular vulnerability assessments to identify and remediate similar issues in other components of their software stack.