CVE-2008-4943 in bulmages-servers
Summary
by MITRE
bulmages-servers 0.11.1 allows local users to overwrite arbitrary files via a symlink attack on the (a) /tmp/error.txt, (b) /tmp/errores.txt, and possibly other temporary files, related to the (1) creabulmafact, (2) creabulmacont, and possibly (3) actualizabulmacont, (4) installbulmages-db, and (5) actualizabulmafact scripts.
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Analysis
by VulDB Data Team • 10/13/2018
The vulnerability identified as CVE-2008-4943 affects bulmages-servers version 0.11.1 and represents a critical file overwrite flaw that stems from improper handling of temporary files within the application's execution environment. This issue manifests when the software creates temporary files in the /tmp directory without adequate security measures to prevent symbolic link attacks, allowing local attackers to manipulate the system's file structure through carefully crafted symlink placements. The vulnerability specifically targets multiple scripts including creabulmafact, creabulmacont, actualizabulmacont, installbulmages-db, and actualizabulmafact, all of which create temporary files at predictable locations that can be exploited by malicious users with local access to the system.
The technical flaw exploits a fundamental weakness in temporary file creation practices where the application performs operations that create files in the /tmp directory without proper atomic creation mechanisms or security checks. When these scripts execute and attempt to write to files like /tmp/error.txt or /tmp/errores.txt, they do not verify whether these target locations are symbolic links or if they point to privileged files. This creates an opportunity for attackers to establish symbolic links to sensitive system files before the vulnerable scripts execute, causing the scripts to overwrite critical files with arbitrary content. The vulnerability is classified as a race condition and improper file handling issue that directly relates to CWE-377 and CWE-378, which address insecure temporary file creation and weak file permissions respectively.
The operational impact of this vulnerability extends beyond simple file overwrites, as it provides attackers with a potential path to privilege escalation and system compromise. Local users who can execute the vulnerable scripts can leverage this weakness to modify system-critical files, potentially leading to unauthorized access, data corruption, or complete system compromise. The attack vector is particularly concerning because it requires minimal privileges and can be executed through normal user accounts, making it an attractive target for attackers seeking to gain elevated system access. The vulnerability affects the entire suite of bulmages-servers scripts, creating a widespread attack surface that could allow for persistent system compromise through multiple attack vectors.
Mitigation strategies for CVE-2008-4943 should focus on implementing secure temporary file creation practices that align with industry standards such as those recommended in the OWASP Secure Coding Practices and NIST guidelines for secure software development. The most effective immediate fix involves modifying the vulnerable scripts to use atomic file creation methods that prevent symlink attacks, such as creating temporary files with unique names and proper permissions, or using system calls that guarantee file creation without symbolic link resolution. Additionally, administrators should implement proper file permission controls and ensure that the /tmp directory has appropriate security settings to prevent unauthorized symbolic link creation. The vulnerability also highlights the importance of the principle of least privilege in script execution, where applications should run with minimal required permissions and avoid creating temporary files in world-writable directories. Organizations should also consider implementing automated security scanning tools that can detect similar vulnerabilities in legacy software systems and apply security patches or workarounds to protect against exploitation through techniques that align with MITRE ATT&CK framework's privilege escalation and defense evasion tactics.