CVE-1999-0477 is a high-severity remote code execution vulnerability affecting multiple early versions (2.0 through 4.0) of the Allaire ColdFusion Application Server. The vulnerability resides in the Expression Evaluator component, specifically in the openfile.cfm script, which improperly restricts access controls. This flaw allows an unauthenticated remote attacker to upload arbitrary files to the server. Since ColdFusion servers often run web applications with elevated privileges, successful exploitation can lead to full compromise of the affected system. The vulnerability does not require authentication or user interaction, and the attack vector is network accessible (AV:N). The ease of exploitation is low complexity (AC:L), making it straightforward for attackers to leverage this flaw. The impact covers confidentiality, integrity, and availability, as attackers can upload malicious scripts or executables, potentially leading to data theft, unauthorized modification, or denial of service. Despite its age and lack of available patches, the vulnerability remains relevant for legacy systems still in operation. No known exploits have been reported in the wild, but the high CVSS score (7.5) reflects the serious risk posed by this vulnerability if exploited.

For European organizations, the impact of CVE-1999-0477 can be significant, especially for those still operating legacy ColdFusion servers in production environments. Exploitation could lead to unauthorized access to sensitive data, disruption of critical web services, and potential lateral movement within corporate networks. Industries such as government, finance, healthcare, and manufacturing that rely on ColdFusion-based applications for internal or customer-facing services are particularly at risk. The ability to upload arbitrary files can facilitate web shell deployment, enabling persistent access and further exploitation. This could result in data breaches, regulatory non-compliance (e.g., GDPR violations), reputational damage, and financial losses. Given the vulnerability’s age, organizations may underestimate the risk, increasing the likelihood of exploitation if legacy systems are exposed to the internet without adequate controls.

Since no official patches are available for this vulnerability, European organizations should prioritize the following specific mitigation steps: 1) Identify and inventory all ColdFusion servers running affected versions (2.0 to 4.0) within their environment. 2) Immediately isolate these legacy servers from public networks or restrict access using network segmentation and firewall rules to limit exposure. 3) Disable or remove the openfile.cfm script or any similar file upload functionality that lacks proper access controls. 4) Implement strict web application firewall (WAF) rules to detect and block attempts to access vulnerable endpoints or upload files. 5) Monitor server logs for suspicious file upload activity or anomalous requests targeting openfile.cfm. 6) Where possible, upgrade to supported versions of ColdFusion or migrate applications to modern, secure platforms. 7) Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect exploitation attempts against ColdFusion vulnerabilities. 8) Conduct regular security assessments and penetration tests focusing on legacy application servers. These targeted measures go beyond generic advice by focusing on legacy system isolation, removal of vulnerable components, and compensating controls to mitigate the absence of patches.