CVE-2008-4987 in xastir
Summary
by MITRE
xastir 1.9.2 allows local users to overwrite arbitrary files via a symlink attack on the (a) /tmp/ldconfig.tmp, (b) /tmp/ldconf.tmp, and (c) /tmp/ld.so.conf temporary files, related to the (1) get-maptools.sh and (2) get_shapelib.sh scripts.
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Analysis
by VulDB Data Team • 04/21/2019
The vulnerability identified as CVE-2008-4987 affects xastir version 1.9.2, a popular amateur radio satellite tracking and mapping application. This issue represents a classic symlink attack vulnerability that exploits insecure temporary file handling within the software's installation and configuration scripts. The flaw specifically targets three temporary files located in the /tmp directory: /tmp/ldconfig.tmp, /tmp/ldconf.tmp, and /tmp/ld.so.conf, which are manipulated by the get-maptools.sh and get_shapelib.sh scripts during the software's initialization process. The vulnerability falls under CWE-377, which addresses insecure temporary file creation, and demonstrates poor security practices in file handling that can be exploited by local attackers to gain unauthorized access to system resources. The attack vector is particularly concerning because it allows local users to overwrite arbitrary files on the system, potentially leading to privilege escalation or system compromise.
The technical implementation of this vulnerability occurs when the xastir application executes the get-maptools.sh and get_shapelib.sh scripts without proper validation of temporary file creation. These scripts create temporary files in the /tmp directory without using secure methods such as mkstemp() or other atomic file creation functions. Instead, they rely on predictable naming conventions that can be exploited by malicious users who create symbolic links with the same names before the legitimate scripts execute. This creates a race condition where the attacker's symbolic link is processed instead of the intended temporary file, allowing arbitrary file overwrite operations. The vulnerability is classified under ATT&CK technique T1059.007 for scripting and T1548.002 for abuse of group privileges, as it leverages local system access to manipulate critical system configuration files.
The operational impact of this vulnerability is significant for systems running xastir 1.9.2, particularly in environments where multiple users have local access to the system. An attacker with local privileges can leverage this weakness to overwrite critical system files, potentially leading to privilege escalation or system instability. The temporary files involved in this attack are specifically related to dynamic library configuration, making the potential damage even more severe as these files control how the system loads shared libraries. The vulnerability affects not only the immediate application but also the broader system security posture, as it can be used to manipulate system libraries that other applications depend upon. This makes the exploit particularly dangerous in multi-user environments or systems where xastir is used with elevated privileges.
Mitigation strategies for CVE-2008-4987 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution is to upgrade to a patched version of xastir that properly handles temporary file creation using secure methods. System administrators should also implement proper file permissions and ownership controls for the /tmp directory, ensuring that temporary files are created with appropriate security contexts. Additionally, the scripts should be modified to use atomic file creation methods such as mkstemp() or similar secure alternatives that prevent symlink attacks. Network segmentation and privilege separation practices should be implemented to limit the potential damage from such vulnerabilities. Organizations should also consider implementing monitoring for suspicious file creation patterns in the /tmp directory and establish regular security audits to identify similar insecure file handling practices in other applications. The vulnerability demonstrates the critical importance of secure coding practices and proper input validation in system administration tools, particularly those that handle system-level configuration changes.