CVE-2012-5355 in xdiagnose
Summary
by MITRE
welcome.py in xdiagnose before 2.5.2ubuntu0.1 allows local users to overwrite arbitrary files via a symlink attack on a temporary file with a predictable name in /tmp.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/19/2021
The vulnerability identified as CVE-2012-5355 affects the xdiagnose package version 2.5.2ubuntu0.1 and earlier, specifically within the welcome.py script component. This issue represents a classic race condition vulnerability that enables local attackers to manipulate system files through symbolic link manipulation. The flaw occurs when the script creates temporary files with predictable naming conventions in the /tmp directory, which is a commonly exploited location for such attacks due to its world-writable nature and lack of proper access controls.
The technical implementation of this vulnerability stems from improper handling of temporary file creation in the welcome.py script. When the script executes, it generates temporary files using predictable names within the /tmp directory without implementing proper security measures such as creating files with unique identifiers or using secure temporary file creation functions. This predictable naming pattern allows malicious local users to establish symbolic links with the same names before the legitimate script creates its temporary files, effectively redirecting the script's file operations to arbitrary locations on the filesystem.
The operational impact of this vulnerability is significant as it provides local attackers with the capability to overwrite any file on the system that the xdiagnose process has write permissions for. This creates a potential escalation path from a local user account to arbitrary file manipulation, which could lead to privilege escalation, data corruption, or even system compromise depending on the target files. The vulnerability is particularly dangerous because it operates within a system diagnostic tool that may run with elevated privileges, and the predictable temporary file naming makes exploitation straightforward and reliable.
From a cybersecurity perspective, this vulnerability aligns with CWE-377: Insecure Temporary File and CWE-378: Creation of Temporary File With Insecure Permissions, both of which are categorized under insecure system design practices in software development. The attack pattern follows the standard symlink attack methodology documented in the MITRE ATT&CK framework under technique T1059.007 for Unix shell commands and T1068 for local privilege escalation. The vulnerability demonstrates poor secure coding practices where developers failed to implement proper temporary file handling mechanisms that would prevent such race conditions.
Mitigation strategies for this vulnerability include immediate patching of the xdiagnose package to version 2.5.2ubuntu0.1 or later, which contains the necessary fixes for secure temporary file creation. System administrators should also implement proper file permissions and access controls on the /tmp directory to limit potential exploitation vectors. Additionally, monitoring for suspicious symbolic link creation in temporary directories and implementing proper temporary file handling practices in all system components can help prevent similar issues. The fix typically involves using secure temporary file creation functions that generate unique filenames or implement proper file locking mechanisms to prevent race conditions. Organizations should also conduct regular security audits of system diagnostic tools and scripts to identify and remediate similar vulnerabilities that could provide attackers with unauthorized file manipulation capabilities.