CVE-1999-1168 is a high-severity local privilege escalation vulnerability found in the install.iss installation script of Internet Security Scanner (ISS) for Linux, version 5.3. The vulnerability arises due to insecure handling of temporary files during the installation process. Specifically, the install.iss script creates temporary files without adequately protecting them against symbolic link (symlink) attacks. A local attacker with access to the system can exploit this by creating a symlink pointing from the expected temporary file to an arbitrary file on the system. When the installation script modifies the temporary file's permissions, it inadvertently changes the permissions of the targeted arbitrary file. This can lead to unauthorized modification of file permissions, potentially allowing the attacker to escalate privileges, compromise system integrity, or gain unauthorized access to sensitive files. The vulnerability requires local access but does not require authentication, and exploitation does not depend on user interaction beyond executing the installation script. The CVSS v2 score of 7.2 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no authentication requirement. No patch is available for this vulnerability, and there are no known exploits in the wild, likely due to the age of the software and the specific conditions required for exploitation.

For European organizations, the impact of this vulnerability depends largely on whether they use the affected version (5.3) of Internet Security Scanner for Linux. ISS was a popular security scanning tool in the late 1990s and early 2000s but has since been largely replaced by modern alternatives. However, legacy systems or environments that still run this version could be at risk. Exploitation could allow a local attacker to escalate privileges, potentially leading to full system compromise. This could result in unauthorized access to sensitive data, disruption of services, or further lateral movement within the network. Given the vulnerability affects file permissions, attackers could manipulate critical system files or security configurations, undermining the organization's security posture. Although the vulnerability requires local access, insider threats or attackers who have gained initial foothold could leverage this to deepen their control. For European organizations with strict data protection regulations such as GDPR, such a compromise could lead to significant legal and reputational consequences.

Since no official patch is available, European organizations should consider the following specific mitigation steps: 1) Immediately discontinue use of Internet Security Scanner version 5.3 and upgrade to a supported, modern vulnerability scanning solution that receives regular security updates. 2) Restrict local access to systems running ISS to trusted administrators only, minimizing the risk of local exploitation. 3) Employ file system monitoring tools to detect unauthorized changes to file permissions or creation of suspicious symlinks, enabling early detection of exploitation attempts. 4) Use mandatory access control (MAC) frameworks such as SELinux or AppArmor to enforce strict permission policies that can prevent unauthorized permission changes even if the script is exploited. 5) Conduct regular audits of legacy systems to identify and remediate outdated software components vulnerable to known exploits. 6) If legacy use is unavoidable, consider running the installation script in a controlled, isolated environment or container to limit potential damage.