CVE-2008-4983 in scilab-bin
Summary
by MITRE
scilab-bin 4.1.2 allows local users to overwrite arbitrary files via a symlink attack on (a) /tmp/SciLink#####1, (b) /tmp/SciLink#####2, (c) /tmp/SciLink#####3, (d) /tmp/*.#####, (e) /tmp/*.#####.res, (f) /tmp/*.#####.err, and (g) /tmp/*.#####.diff temporary files, related to the (1) scilink, (2) scidoc, and (3) scidem scripts.
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Analysis
by VulDB Data Team • 08/26/2019
The vulnerability described in CVE-2008-4983 represents a critical symlink attack flaw affecting scilab-bin version 4.1.2, which operates within the scientific computing and engineering simulation domain. This issue stems from improper handling of temporary files during the execution of scilab scripts, creating a significant security risk for local users who can exploit the system's predictable temporary file naming conventions to gain unauthorized file overwrite capabilities. The vulnerability specifically targets multiple temporary file patterns that are created during the execution of scilink, scidoc, and scidem scripts, making it particularly dangerous as it affects core functionality of the scientific computing environment.
The technical flaw manifests through the predictable naming of temporary files using patterns such as /tmp/SciLink#####1, /tmp/SciLink#####2, /tmp/SciLink#####3, and various wildcard patterns like /tmp/.#####, /tmp/.#####.res, /tmp/.#####.err, and /tmp/.#####.diff, where the hash symbols represent numeric placeholders. When scilab-bin executes these scripts, it creates temporary files in the /tmp directory without proper security checks or atomic operations, allowing local attackers to establish symbolic links with the same names before the legitimate processes create the actual files. This race condition vulnerability falls under CWE-367, specifically addressing Time-of-Check to Time-of-Use (TOCTOU) flaws, where the system checks for file existence and then uses the file without revalidation, creating a window for exploitation.
The operational impact of this vulnerability extends beyond simple file overwrite capabilities, as it can potentially lead to privilege escalation, code execution, or data corruption within the scientific computing environment. Attackers can leverage this weakness to replace critical system files, modify configuration data, or inject malicious content into the temporary files that scilab processes may later read or execute. The vulnerability affects users who have local access to systems running scilab-bin 4.1.2, making it particularly concerning in multi-user environments or shared computing systems where local privilege escalation could provide attackers with broader system access. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for command and scripting interpreter execution and T1068 for local privilege escalation, as the exploitation could potentially be used to gain elevated privileges through file system manipulation.
Mitigation strategies for CVE-2008-4983 require immediate implementation of proper temporary file handling mechanisms, including the use of secure temporary file creation functions that prevent symbolic link attacks, such as those provided by the mkstemp() system call in Unix-like systems. System administrators should ensure that all temporary files are created with appropriate permissions and that symbolic link checks are performed before file operations. The recommended approach involves implementing atomic file creation processes that eliminate the race condition window, using secure temporary directories with restricted permissions, and ensuring that scripts do not create predictable temporary file names. Additionally, updating to newer versions of scilab-bin that address this specific vulnerability or implementing proper input validation and file system access controls can significantly reduce the attack surface. Organizations should also consider implementing monitoring and alerting for suspicious temporary file creation patterns and establish regular security audits to identify similar vulnerabilities in other scientific computing applications.