CVE-2013-6494 in fedup
Summary
by MITRE
fedup 0.9.0 in Fedora 19, 20, and 21 uses a temporary directory with a static name for its download cache, which allows local users to cause a denial of service (prevention of system updates).
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability identified as CVE-2013-6494 affects the fedup utility version 0.9.0 distributed with Fedora 19, 20, and 21 operating systems. This issue represents a significant security flaw in the package management update process that could be exploited by local attackers to disrupt system operations. The fedup utility serves as a critical component for performing system updates in Fedora environments, making this vulnerability particularly concerning from a system integrity perspective.
The technical flaw stems from the implementation of a static temporary directory name within the download cache mechanism of fedup. This design decision creates a predictable path that local users can exploit to manipulate the update process. When fedup performs its download operations, it creates cache files in a predetermined temporary directory location rather than utilizing a dynamically generated or randomized path. This static naming convention violates fundamental security principles for temporary file handling and creates predictable attack vectors.
The operational impact of this vulnerability manifests as a potential denial of service condition that specifically targets system update functionality. Local users who exploit this weakness can interfere with the update process by either pre-creating files in the static temporary directory or by manipulating existing cache files. This manipulation prevents the system from properly completing update operations, effectively blocking users from applying security patches or system enhancements. The vulnerability essentially creates a scenario where unauthorized local access can result in complete system update paralysis.
From a cybersecurity perspective, this vulnerability aligns with CWE-377, which addresses insecure temporary file creation practices, and represents a variant of the broader class of privilege escalation and denial of service attacks. The ATT&CK framework categorizes this as a privilege escalation technique through local system manipulation, where adversaries leverage predictable file paths to gain unauthorized control over system processes. The vulnerability demonstrates how seemingly minor implementation details in system utilities can create substantial security risks that affect the entire update ecosystem.
The mitigation strategy for this vulnerability requires immediate patching of the fedup utility to implement dynamic temporary directory creation with randomized names or unique identifiers. System administrators should prioritize applying the official Fedora security updates that address this specific issue. Additionally, implementing proper temporary file handling practices through the use of secure temporary directory creation functions and ensuring proper file permissions can prevent similar vulnerabilities from emerging in other applications. Organizations should also consider monitoring for unauthorized modifications to update cache directories and implementing automated checks to verify the integrity of system update processes. The remediation process must include verification that temporary directories are created with appropriate security attributes and that the update mechanisms no longer rely on predictable static paths for cache management.