CVE-2005-3885 in Inkscape
Summary
by MITRE
The ps2epsi extension shell script (ps2epsi.sh) in Inkscape before 0.41 allows local users to overwrite arbitrary files via a symlink attack on the tmpepsifile.epsi temporary file.
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Analysis
by VulDB Data Team • 08/03/2019
The vulnerability described in CVE-2005-3885 represents a critical security flaw in the Inkscape vector graphics editor version 0.41 and earlier. This issue specifically affects the ps2epsi extension shell script which is used to convert PostScript files to EPSI format. The vulnerability arises from improper handling of temporary files during the extension execution process, creating a predictable temporary file naming pattern that can be exploited through symbolic link attacks. The flaw exists because the script creates temporary files with known names without sufficient randomness or security checks, making them susceptible to manipulation by local attackers who can establish symbolic links to target sensitive files.
The technical implementation of this vulnerability follows a classic race condition pattern where the attacker exploits the time gap between temporary file creation and file access. When Inkscape executes the ps2epsi extension, it generates a temporary file named tmpepsifile.epsi in a predictable location. An attacker with access to the system can create a symbolic link with the same name in the target directory before the script executes, causing the script to write its output to the attacker-controlled file instead of the intended temporary location. This allows the attacker to overwrite arbitrary files with potentially malicious content, effectively bypassing normal file permissions and access controls.
The operational impact of this vulnerability extends beyond simple file overwrites, as it enables local privilege escalation and arbitrary code execution in certain scenarios. Attackers can leverage this vulnerability to replace critical system files, configuration files, or even executable binaries with malicious versions that will be executed by the system. The vulnerability affects all local users who have access to execute the ps2epsi extension, making it particularly dangerous in multi-user environments where attackers might exploit this to gain elevated privileges. From a security perspective, this vulnerability demonstrates poor secure coding practices and highlights the importance of proper temporary file handling in shell scripts and system utilities.
This vulnerability maps directly to CWE-377: Insecure Temporary File and CWE-378: Poor Randomization, both of which are categorized under insecure coding practices that lead to predictable resource locations. The attack pattern aligns with ATT&CK technique T1059.007 for Unix Shell and T1068 for Exploitation for Privilege Escalation, as attackers can use this vulnerability to execute arbitrary code and potentially escalate their privileges. The mitigation strategies should focus on implementing proper temporary file handling mechanisms including using secure temporary file creation functions, implementing proper file permission controls, and ensuring that temporary files are created with unpredictable names and proper access controls. System administrators should also consider disabling unnecessary extensions and applying the security patch that was released with Inkscape version 0.41 to address this vulnerability.