CVE-2008-5148 in gnetlist
Summary
by MITRE
sch2eaglepos.sh in geda-gnetlist 1.4.0 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/##### temporary file.
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Analysis
by VulDB Data Team • 08/21/2019
The vulnerability identified as CVE-2008-5148 resides within the sch2eaglepos.sh script component of geda-gnetlist version 1.4.0, representing a classic insecure temporary file creation flaw that enables local privilege escalation through symbolic link manipulation. This issue manifests when the script creates temporary files in the /tmp directory using a predictable naming pattern with multiple hash characters, making it susceptible to race condition attacks where malicious users can establish symbolic links before the script processes them.
The technical implementation of this vulnerability follows a well-documented pattern that aligns with CWE-377, which addresses insecure temporary file creation practices in software applications. The sch2eaglepos.sh script generates temporary files using a naming convention that includes multiple hash characters in the /tmp directory, creating predictable file paths that attackers can exploit through symlink attacks. When the script operates with elevated privileges, particularly during the execution of the geda-gnetlist tool, local users can manipulate the temporary file creation process by establishing symbolic links to target files of their choice, effectively allowing them to overwrite arbitrary files on the system with the privileges of the executing process.
This vulnerability operates under the principles of privilege escalation through insecure file handling as described in the ATT&CK framework under technique T1068, which covers the exploitation of legitimate credentials and privileges to gain elevated access. The operational impact of this flaw extends beyond simple file overwriting, as it can potentially allow attackers to modify critical system files, configuration data, or even inject malicious code into the execution flow of the geda-gnetlist utility. The attack vector leverages the timing window between temporary file creation and file processing, creating a window where symbolic links can be successfully placed before the script performs its operations.
The security implications of this vulnerability are particularly concerning given that geda-gnetlist is a tool used for electronic design automation and circuit schematic processing, where the integrity of the tool's execution environment is paramount. Attackers could potentially exploit this weakness to modify the behavior of the netlist generation process, leading to corrupted designs or even system compromise if the tool is executed with elevated privileges. The vulnerability's impact is further amplified by the fact that it requires minimal privileges to exploit, making it accessible to any local user who can create symbolic links in the /tmp directory, and the attack can be executed without requiring network access or complex exploitation techniques.
Mitigation strategies for CVE-2008-5148 should focus on implementing secure temporary file creation practices that align with industry standards such as those outlined in the OWASP Secure Coding Practices. The most effective remediation involves replacing the insecure temporary file creation pattern with secure alternatives that utilize unique, unpredictable filenames and proper file permission settings. System administrators should ensure that the geda-gnetlist tool is not executed with elevated privileges when possible, and that proper file system permissions are enforced to prevent unauthorized symbolic link creation. Additionally, the script should be updated to use atomic temporary file creation methods that prevent race conditions, such as creating files with exclusive access flags or using the mktemp command with appropriate security parameters to generate unpredictable temporary file paths. Organizations should also implement regular security audits and vulnerability assessments to identify similar insecure file handling patterns in other software components that may be vulnerable to the same class of attack.