CVE-1999-0155 is a high-severity vulnerability found in the Ghostscript software, specifically affecting versions 2.6 through 3.22. Ghostscript is a widely used interpreter for PostScript and PDF files, often employed in printing and document processing workflows. The vulnerability arises from the use of the -dSAFER option, which is intended to restrict the execution environment and prevent unsafe operations. However, in the affected versions, this option does not adequately restrict command execution, allowing remote attackers to execute arbitrary commands on the vulnerable system without authentication. The vulnerability is exploitable over the network (AV:N), requires no authentication (Au:N), and has low attack complexity (AC:L). Successful exploitation can compromise confidentiality, integrity, and availability (C:P/I:P/A:P) of the affected systems. Despite the age of this vulnerability (published in 1995), it remains significant for legacy systems still running outdated Ghostscript versions. No patches are available for these versions, and no known exploits are currently reported in the wild, but the potential for remote code execution makes it a critical risk if such systems are exposed.

For European organizations, the impact of this vulnerability can be substantial if legacy systems running vulnerable Ghostscript versions are still in use, particularly in environments processing PostScript or PDF files automatically, such as print servers, document management systems, or embedded devices. Exploitation could lead to unauthorized command execution, resulting in data breaches, system compromise, or disruption of critical services. Confidential information could be exposed or altered, and attackers could gain persistent access or disrupt operations. Given the high CVSS score (7.5) and the remote, unauthenticated nature of the exploit, organizations that have not updated or isolated legacy systems are at risk. The threat is especially relevant for sectors with heavy document processing needs, including government, legal, publishing, and manufacturing industries prevalent in Europe.

Since no patches are available for the affected versions, European organizations should prioritize the following mitigations: 1) Identify and inventory all systems running Ghostscript versions 2.6 through 3.22. 2) Upgrade to a modern, supported version of Ghostscript where the vulnerability is fixed. 3) If upgrading is not immediately possible, isolate vulnerable systems from untrusted networks to prevent remote exploitation. 4) Restrict network access to systems running Ghostscript, especially print servers and document processing endpoints. 5) Employ application whitelisting and strict execution policies to limit the ability of attackers to execute arbitrary commands. 6) Monitor logs and network traffic for unusual activity indicative of exploitation attempts. 7) Consider replacing legacy document processing workflows with more secure alternatives. These steps go beyond generic advice by focusing on legacy system identification, network isolation, and compensating controls.