CVE-2008-0806 in wyrd
Summary
by MITRE
wyrd 1.4.3b allows local users to overwrite arbitrary files via a symlink attack on the wyrd-tmp.[USERID] temporary file.
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Analysis
by VulDB Data Team • 08/06/2019
The vulnerability identified as CVE-2008-0806 affects wyrd version 1.4.3b, a tool designed for managing and organizing personal information. This issue represents a classic symlink attack scenario that exploits improper handling of temporary files within the application's operational environment. The flaw specifically manifests when wyrd creates temporary files using predictable naming conventions that include user identifiers, making it susceptible to manipulation by local attackers who can establish malicious symbolic links before the application attempts to write to these temporary locations.
The technical implementation of this vulnerability stems from the application's failure to properly validate or secure temporary file creation processes. When wyrd operates with elevated privileges or specific user contexts, it generates temporary files named wyrd-tmp.USERID where USERID corresponds to the actual user identifier. Local attackers can exploit this predictable naming pattern by creating symbolic links with the same names in directories where wyrd expects to create its temporary files. This allows attackers to redirect file operations to arbitrary locations on the filesystem, potentially overwriting critical system files or configuration data with malicious content. The vulnerability operates at the file system level and demonstrates poor privilege separation and inadequate temporary file handling practices.
The operational impact of this vulnerability extends beyond simple file overwriting capabilities, as it enables attackers to potentially escalate privileges or disrupt system operations. Since wyrd may run with elevated permissions or access sensitive user data, successful exploitation could allow attackers to modify system configuration files, inject malicious code into application processes, or establish persistent access mechanisms. The vulnerability affects all local users who can create symbolic links in the target directory, making it particularly concerning in multi-user environments where attackers might gain access to less privileged accounts. This issue aligns with CWE-377, which addresses insecure temporary file creation practices, and represents a significant concern for systems where wyrd is used in security-sensitive contexts.
Mitigation strategies for this vulnerability require immediate attention through proper temporary file handling implementations and privilege management. System administrators should ensure that wyrd is updated to versions that properly handle temporary files using secure creation methods such as creating files with exclusive access permissions or using secure temporary directories with appropriate access controls. The application should implement checks to verify that temporary files are not symbolic links before writing to them, and should use random or unpredictable naming schemes for temporary files to prevent attackers from pre-creating malicious links. Organizations should also consider implementing privilege separation techniques and monitoring for unusual file system modifications in directories where temporary files are created, as outlined in the attack patterns described by the attack technique T1059.102 for executing commands through file system manipulation.