CVE-1999-0859 is a vulnerability found in the Solaris operating system's arp utility, specifically affecting versions 2.5.1, 2.6, 7.0, 5.5.1, and 5.7. The arp command is used to manipulate the system's Address Resolution Protocol cache, which maps IP addresses to MAC addresses. The vulnerability arises from the use of the -f parameter, which allows a local user to specify a file for the arp command to parse. Due to improper handling of this parameter, the arp utility can be tricked into reading arbitrary files on the system and listing lines that do not parse correctly. This behavior effectively allows local users to read portions of files they would not normally have access to, leading to an information disclosure vulnerability. The vulnerability does not allow modification of files or system integrity compromise, nor does it affect system availability. Exploitation requires local access to the system, and no elevated privileges are necessary to trigger the file reading behavior. The vulnerability has a low CVSS score of 2.1, reflecting its limited impact and exploitation scope. No patches are available for this vulnerability, and there are no known exploits in the wild. Given the age of the affected Solaris versions, this vulnerability is primarily relevant in legacy environments that still run these older Solaris releases.

For European organizations, the impact of CVE-1999-0859 is generally low due to the requirement for local access and the limited scope of information disclosure. However, in environments where legacy Solaris systems are still operational—such as certain government agencies, financial institutions, or industrial control systems—this vulnerability could allow unauthorized local users to glean sensitive configuration or system information. This information could potentially be used to facilitate further attacks or privilege escalation attempts. The confidentiality impact is limited to file content exposure, with no direct impact on system integrity or availability. Given the low severity and the absence of known exploits, the immediate risk is minimal, but organizations with legacy Solaris deployments should be aware of this vulnerability as part of their overall security posture.

Since no official patches are available for this vulnerability, mitigation should focus on compensating controls. Organizations should restrict local access to Solaris systems to trusted personnel only and enforce strict access controls and monitoring to detect unauthorized local activity. Disabling or restricting the use of the arp utility for non-administrative users can reduce the risk of exploitation. Additionally, migrating legacy Solaris systems to supported and updated operating system versions is strongly recommended to eliminate this and other legacy vulnerabilities. Regular auditing of system files and logs can help identify attempts to exploit this vulnerability. Employing host-based intrusion detection systems (HIDS) to monitor unusual arp command usage may also provide early warning of exploitation attempts.