CVE-2008-4957 in gccxml
Summary
by MITRE
find_flags in Kitware GCC-XML (gccxml) 0.9.0 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/*.cxx temporary file.
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Analysis
by VulDB Data Team • 08/03/2021
The vulnerability identified as CVE-2008-4957 affects Kitware GCC-XML version 0.9.0 and represents a classic symlink attack scenario that exploits improper handling of temporary files during the compilation process. This flaw exists within the find_flags function which is part of the GCC-XML toolset used for parsing c++ source code and generating xml representations of the code structure. The vulnerability arises from the tool's insecure temporary file creation practices where it creates temporary files with predictable names in the /tmp directory without proper security checks. When a local attacker can manipulate the symlink structure of the /tmp directory, they can redirect the tool's write operations to arbitrary files on the system, potentially allowing privilege escalation or data corruption.
The technical implementation of this vulnerability stems from the lack of proper file permission checks and atomic file creation mechanisms within the GCC-XML tool. When the find_flags function processes source files, it generates temporary .cxx files in the /tmp directory using a predictable naming scheme that does not incorporate sufficient entropy or security measures to prevent symlink attacks. This behavior creates a race condition where an attacker can establish a symbolic link pointing to a target file before the legitimate tool attempts to write to the temporary location. The vulnerability is classified under CWE-377 as "Insecure Temporary File" and also relates to CWE-378 as "Creation of Temporary File With Insecure Permissions" which directly addresses the insecure handling of temporary resources in software applications.
The operational impact of this vulnerability extends beyond simple file overwriting capabilities as it provides attackers with a mechanism to potentially compromise the integrity of the build environment and system security. Local attackers can leverage this vulnerability to overwrite critical system files, configuration files, or even executable binaries, leading to privilege escalation or persistent backdoor installation. The attack vector requires local access to the system but can be particularly dangerous in environments where GCC-XML is used in automated build processes or where users with lower privileges might have access to systems running this tool. This vulnerability also aligns with ATT&CK technique T1059.001 for "Command and Scripting Interpreter: Visual Basic" and T1068 for "Exploitation for Privilege Escalation" as it can be used to establish persistent access or escalate privileges within the compromised system.
Mitigation strategies for this vulnerability focus on both immediate defensive measures and long-term architectural improvements. System administrators should ensure that GCC-XML is updated to versions that properly handle temporary files with secure creation mechanisms, such as using mkstemp() or similar secure file creation functions that prevent symlink attacks. The tool should be configured to create temporary files in directories with restricted permissions and proper ownership controls. Additionally, implementing proper file permission checks and ensuring that temporary files are created atomically can prevent this class of vulnerability. Organizations should also consider restricting access to the /tmp directory or implementing more secure temporary file handling practices in their build environments. The vulnerability demonstrates the importance of following secure coding practices as outlined in OWASP Secure Coding Practices and should be addressed through comprehensive security testing including static code analysis and dynamic vulnerability assessment.