CVE-2005-2471 in netpbm
Summary
by MITRE
pstopnm in netpbm does not properly use the "-dSAFER" option when calling Ghostscript to convert a PostScript file into a (1) PBM, (2) PGM, or (3) PNM file, which allows external user-assisted attackers to execute arbitrary commands.
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Analysis
by VulDB Data Team • 06/30/2025
The vulnerability identified as CVE-2005-2471 resides within the pstopnm utility of the netpbm package, a collection of tools for converting between various image formats. This flaw represents a critical security issue that stems from improper handling of the "-dSAFER" parameter when interfacing with the Ghostscript rendering engine. The vulnerability specifically affects the conversion processes that generate PBM, PGM, and PNM image formats from PostScript files, creating a pathway for malicious code execution through user-assisted attacks.
The technical root cause of this vulnerability lies in the failure of pstopnm to correctly implement the "-dSAFER" security option when invoking Ghostscript. This parameter is designed to restrict Ghostscript's access to the local file system and prevent potentially dangerous operations such as file reading, writing, or system command execution. When pstopnm omits or improperly applies this safeguard, it allows attackers to craft malicious PostScript files that contain embedded commands which Ghostscript will execute with the privileges of the user running pstopnm. The vulnerability operates under the principle of command injection, where untrusted input is passed directly to the system shell without proper sanitization or validation.
The operational impact of this vulnerability is severe and directly relates to the principle of least privilege in cybersecurity. An attacker who can convince a victim to process a malicious PostScript file through pstopnm can potentially execute arbitrary commands on the target system. This could lead to unauthorized access, data exfiltration, system compromise, or further lateral movement within a network. The user-assisted nature of the attack means that social engineering or trickery is required to get the victim to process the malicious file, but once executed, the consequences can be devastating. This vulnerability specifically aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic example of how insufficient input validation and improper privilege management can create dangerous attack vectors.
Mitigation strategies for this vulnerability must address both the immediate technical flaw and broader security practices. The primary fix involves updating the pstopnm utility to properly implement the "-dSAFER" parameter when invoking Ghostscript, ensuring that all file system operations and command execution are properly sandboxed. System administrators should also consider implementing additional security controls such as restricting file processing permissions, deploying file type validation mechanisms, and ensuring that netpbm packages are kept up to date with security patches. Organizations should also review their broader security posture to prevent similar issues in other applications that interface with external rendering engines or command execution utilities. This vulnerability demonstrates the critical importance of security-by-design principles and the necessity of proper parameter handling when integrating with external systems, aligning with ATT&CK technique T1059 for executing commands and T1203 for exploitation for privilege escalation.