CVE-2008-4978 in radiance
Summary
by MITRE
radiance 3R9+20080530 allows local users to overwrite arbitrary files via a symlink attack on (a) /tmp/opt.fmt, (b) /tmp/out#####.fmt, (c) /tmp/tf#####.dat, (d) /tmp/gsf#####, (e) /tmp/sc#####.sh, (f) /tmp/il#####.pic, (g) /tmp/tl#####.pic, (h) /tmp/ds#####.pic, (i) /tmp/tfa#####, and (j) /tmp/sed##### temporary files, related to the (1) optics2rad, (2) pdelta, (3) dayfact, and (4) raddepend scripts.
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Analysis
by VulDB Data Team • 10/14/2018
The vulnerability described in CVE-2008-4978 represents a critical file system security flaw within the radiance 3R9+20080530 software suite, specifically targeting temporary file handling mechanisms across multiple scripts. This issue stems from improper handling of temporary files that are created with predictable naming patterns in the /tmp directory, creating an exploitable race condition scenario. The vulnerability affects several key components including optics2rad, pdelta, dayfact, and raddepend scripts, which are integral parts of the radiance rendering software used for lighting simulation and architectural visualization. The flaw enables local attackers to manipulate the system by creating symbolic links to target files before the vulnerable scripts process them, effectively allowing arbitrary file overwrite operations.
The technical implementation of this vulnerability follows a classic symlink attack pattern where attackers can exploit the predictable temporary file names to gain unauthorized access to the file system. The affected temporary files include various formats such as .fmt, .dat, .sh, .pic, and .sed files with patterns like tf#####.dat, sc#####.sh, and il#####.pic, where the hash symbols represent numerical placeholders. This predictable naming convention makes it possible for malicious users to establish symbolic links in the /tmp directory that will be dereferenced by the vulnerable scripts during execution. 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." The attack vector specifically targets the lack of proper file permission checking and atomic file creation mechanisms within the software's temporary file handling logic.
The operational impact of this vulnerability extends beyond simple file overwrites to potentially allow privilege escalation and system compromise. Local attackers who can execute the vulnerable scripts can leverage this weakness to modify critical system files, inject malicious code into the rendering pipeline, or even overwrite configuration files that could affect the entire system's functionality. The temporary files involved in this vulnerability are created with insufficient security measures, allowing attackers to manipulate the file system during the execution of legitimate processes. This creates a window of opportunity where attackers can substitute their own content for legitimate temporary files, potentially leading to code execution or data corruption. The vulnerability affects systems where the radiance software is installed and executed with elevated privileges, making it particularly dangerous in multi-user environments or when the software is used in automated workflows.
Mitigation strategies for this vulnerability require immediate implementation of proper temporary file handling practices that prevent symlink attacks. The recommended approach includes using secure temporary file creation methods such as mkstemp or similar atomic operations that ensure file creation is both exclusive and secure. System administrators should also implement proper file permission controls and consider using non-predictable temporary file names or directories with restricted access. The vulnerability aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" and T1078.004 for "Valid Accounts: Cloud Accounts" when considering how attackers might leverage this weakness in automated environments. Additionally, implementing proper input validation and file access controls within the affected scripts would prevent unauthorized file system manipulation. Organizations should also consider updating to newer versions of the radiance software where these temporary file handling issues have been addressed, and conduct regular security audits of all software components that create temporary files to prevent similar vulnerabilities from being introduced.