CVE-2008-6398 in sng
Summary
by MITRE
sng_regress in SNG 1.0.2 allows local users to overwrite arbitrary files via a symlink attack on the (1) /tmp/recompiled$$.png, (2) /tmp/decompiled$$.sng, and (3) /tmp/canonicalized$$.sng temporary files.
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Analysis
by VulDB Data Team • 10/31/2018
The vulnerability identified as CVE-2008-6398 resides within the SNG 1.0.2 software suite, specifically within the sng_regress component that handles regression testing operations. This flaw represents a classic race condition vulnerability that exploits the insecure creation of temporary files in a predictable location. The issue manifests when the application creates temporary files using predictable naming patterns such as /tmp/recompiled$$.png, /tmp/decompiled$$.sng, and /tmp/canonicalized$$.sng where the $$ represents process identifiers. The vulnerability stems from the application's failure to properly secure these temporary files, creating an opportunity for malicious local users to manipulate the file system through symbolic link attacks.
The technical exploitation of this vulnerability occurs through a time-of-check to time-of-use race condition pattern where an attacker creates symbolic links with the same names as the temporary files that the vulnerable application will later create. When the application executes and attempts to write to these predictable temporary file locations, it inadvertently writes to files controlled by the attacker rather than the intended temporary files. This allows the attacker to overwrite arbitrary files on the system with arbitrary content, potentially leading to privilege escalation or arbitrary code execution depending on the target files and permissions. The vulnerability directly maps to CWE-367 which defines the Time-of-Check to Time-of-Use vulnerability pattern, and represents a classic example of insecure temporary file handling that violates the principle of least privilege.
From an operational impact perspective, this vulnerability enables local privilege escalation attacks where a malicious user can overwrite critical system files, configuration files, or even binaries with malicious content. The attacker can leverage this to gain elevated privileges, modify system behavior, or establish persistence mechanisms within the target environment. The vulnerability is particularly concerning because it requires minimal privileges to exploit and can be combined with other attack vectors to create more sophisticated compromise scenarios. The impact extends beyond simple file overwrites as attackers can potentially overwrite system binaries or configuration files that are later executed by privileged processes, creating a potential path to complete system compromise.
Mitigation strategies for CVE-2008-6398 should focus on implementing secure temporary file handling practices that align with the principle of least privilege and proper file system permissions. Organizations should ensure that temporary files are created with secure permissions, using the O_CREAT and O_EXCL flags to prevent race conditions, and avoiding predictable naming patterns for temporary files. The application should be modified to create temporary files in directories with restricted permissions or use secure temporary file creation functions that prevent symbolic link attacks. Additionally, implementing proper input validation and using sandboxing techniques can help reduce the attack surface. This vulnerability demonstrates the importance of following secure coding practices as outlined in the OWASP Secure Coding Practices and aligns with ATT&CK technique T1059 for execution through file permissions and T1068 for privilege escalation through local file manipulation. System administrators should also consider implementing monitoring for suspicious file system activities and temporary file creation patterns to detect potential exploitation attempts.