CVE-2008-4975 in newsgate
Summary
by MITRE
mkmailpost in newsgate 1.6 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/mmp##### temporary file.
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Analysis
by VulDB Data Team • 10/14/2018
The vulnerability identified as CVE-2008-4975 resides within the mkmailpost component of newsgate version 1.6, representing a classic race condition and insecure temporary file handling flaw that enables local privilege escalation through symbolic link manipulation. This issue manifests when the mkmailpost utility creates temporary files in the /tmp directory using a predictable naming pattern with the prefix mmp followed by five hash characters. The vulnerability stems from the application's failure to properly validate or secure temporary file creation processes, creating an exploitable window where malicious users can establish symbolic links before the legitimate file operations occur. The flaw directly maps to CWE-362, which describes race conditions in file operations, and CWE-367, which addresses the execution of malicious code through insecure temporary file handling. Attackers can leverage this vulnerability by creating symbolic links in the /tmp directory with names matching the expected temporary file pattern, thereby causing the mkmailpost utility to write data to unintended locations, potentially overwriting critical system files or configuration data.
The operational impact of this vulnerability extends beyond simple file overwriting, as it provides attackers with a mechanism to manipulate the system's file permissions and potentially execute arbitrary code with elevated privileges. When local users can control the contents of files that are written to by mkmailpost, they gain the ability to modify system binaries, configuration files, or other sensitive data that the utility might be configured to update. The attack vector relies on the attacker's ability to predict the temporary filename generation pattern and create the corresponding symbolic links before the legitimate file operations occur, making this a time-sensitive exploit that requires precise timing and system access. The vulnerability's exploitation directly aligns with ATT&CK technique T1059, which involves the execution of malicious code through system utilities, and T1068, which covers privilege escalation through local system manipulation. This flaw particularly affects Unix-like systems where the /tmp directory is world-writable and where the mkmailpost utility operates with sufficient privileges to modify system-critical files.
Mitigation strategies for CVE-2008-4975 must address both the immediate security gap in temporary file handling and implement broader system hardening measures. System administrators should immediately patch the newsgate software to a version that properly handles temporary file creation through secure methods such as creating files with unique identifiers and verifying file ownership before writing to them. The implementation of proper file permissions and secure temporary file creation practices should be enforced, including using mkstemp or similar functions that create files atomically and ensure exclusive access. Additionally, the system should be configured to use a non-world-writable temporary directory or implement proper file access controls for the /tmp directory. Security monitoring should be enhanced to detect suspicious symbolic link creation patterns in temporary directories, and privilege separation should be enforced to ensure that utilities like mkmailpost operate with minimal required permissions. The vulnerability highlights the importance of following secure coding practices and implementing proper input validation and file access controls as recommended in security frameworks such as the OWASP Secure Coding Practices and NIST Special Publication 800-125, which emphasize the need for robust temporary file handling to prevent such race condition attacks.