CVE-2008-5367 in ppp-udeb
Summary
by MITRE
ip-up in ppp-udeb 2.4.4rel on Debian GNU/Linux allows local users to overwrite arbitrary files via a symlink attack on the /tmp/resolv.conf.tmp temporary file.
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Analysis
by VulDB Data Team • 10/19/2018
The vulnerability identified as CVE-2008-5367 resides within the ppp-udeb package version 2.4.4rel distributed with Debian GNU/Linux systems. This issue manifests in the ip-up script which is executed during Point-to-Point Protocol (PPP) connection establishment processes. The flaw represents a classic race condition vulnerability that occurs when temporary files are created without proper security measures, specifically affecting the /tmp/resolv.conf.tmp file used for DNS resolution configuration during network setup.
The technical exploitation of this vulnerability involves a symlink attack pattern where local attackers can create malicious symbolic links that point to sensitive system files. When the ip-up script executes and attempts to write to /tmp/resolv.conf.tmp, it inadvertently overwrites files that the attacker has symlinked to the temporary location. This occurs because the script creates temporary files without proper file descriptor validation or atomic creation mechanisms, allowing attackers to manipulate the target file paths through symbolic link manipulation.
The operational impact of this vulnerability extends beyond simple file overwriting capabilities, as it enables attackers to modify critical system configuration files that control DNS resolution behavior. This can lead to man-in-the-middle attacks, DNS poisoning, or complete disruption of network services that depend on proper DNS resolution. The vulnerability affects systems where ppp-udeb is installed and used for network configuration, particularly impacting Debian-based systems during PPP connection setup procedures. Attackers can leverage this to gain persistent access to network configuration data or cause service disruptions by replacing legitimate DNS configuration files with malicious alternatives.
Mitigation strategies for CVE-2008-5367 require immediate patching of the affected ppp-udeb package to ensure proper temporary file handling and atomic creation mechanisms are implemented. System administrators should also implement proper file system permissions and consider using more secure temporary file creation methods such as mkstemp() instead of relying on predictable temporary file names. The vulnerability aligns with CWE-377, which addresses insecure temporary file creation, and relates to ATT&CK technique T1059 for privilege escalation through local system modifications. Additionally, implementing proper file system monitoring and access controls around /tmp directory usage can help detect and prevent exploitation attempts, while regular security audits should verify that no symbolic links exist in critical temporary file locations during system configuration processes.