CVE-2008-4952 in emacs-jabber
Summary
by MITRE
emacs-jabber in emacs-jabber 0.7.91 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/*.log temporary file.
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Analysis
by VulDB Data Team • 10/13/2018
The vulnerability described in CVE-2008-4952 represents a classic symlink attack scenario that exploits improper handling of temporary files in the emacs-jabber package version 0.7.91. This issue falls under the category of insecure temporary file creation, which is a well-documented security weakness that has been consistently identified in numerous applications over the years. The vulnerability specifically affects local users who can manipulate the system to overwrite arbitrary files through a carefully crafted symbolic link attack against a temporary file located in the /tmp directory with a .log extension.
The technical flaw stems from the application's failure to properly validate or secure temporary file creation processes. When emacs-jabber creates temporary log files in the /tmp directory, it does not implement proper security measures to prevent symlink attacks. Attackers can create symbolic links with the same names as the temporary files that the application intends to create, effectively redirecting the application's write operations to arbitrary locations on the filesystem. This vulnerability is particularly dangerous because it allows local users to potentially overwrite critical system files, configuration files, or even files belonging to other users with elevated privileges, depending on the application's execution context.
The operational impact of this vulnerability extends beyond simple file overwrites and can lead to significant system compromise. An attacker with local access can leverage this weakness to escalate privileges, modify system configurations, or even inject malicious code into critical system components. The attack vector is relatively straightforward and requires minimal privileges, making it an attractive target for attackers who have already gained local access to a system. The vulnerability is particularly concerning in multi-user environments where the application might run with elevated privileges or where users have the ability to create symbolic links in the /tmp directory.
From a cybersecurity perspective, this vulnerability aligns with several key concepts in the Common Weakness Enumeration framework, specifically mapping to CWE-354, which addresses "Improper Check for Unusual or Exceptional Conditions" and CWE-377, which covers "Insecure Temporary Files." The attack pattern also corresponds to techniques documented in the MITRE ATT&CK framework under the "Persistence" and "Privilege Escalation" domains, as attackers can use such vulnerabilities to maintain access or elevate their privileges within the compromised system. The vulnerability demonstrates how seemingly minor implementation flaws in temporary file handling can result in significant security implications, highlighting the importance of proper file system security practices in application development.
The mitigation strategies for this vulnerability involve implementing secure temporary file creation practices that prevent symlink attacks. Applications should avoid creating temporary files in world-writable directories like /tmp and instead use secure methods such as creating temporary files with unique, unpredictable names and proper file permissions. Additionally, applications should verify that temporary files are created with appropriate ownership and permissions, and they should avoid using predictable naming schemes that attackers can exploit. System administrators should also ensure that the /tmp directory has proper permissions and that users cannot create symbolic links in this directory without proper authorization. The vulnerability underscores the critical importance of following secure coding practices and conducting thorough security reviews of file system operations, particularly those involving temporary files and directories.