CVE-1999-0007 is a medium-severity vulnerability affecting multiple versions of the Stonghold Web Server product by c2net. The vulnerability involves the leakage of information from SSL-encrypted sessions due to weaknesses in the implementation of the PKCS #1 standard, which is used for RSA encryption padding. Specifically, the flaw allows attackers to gain partial information about encrypted SSL sessions, potentially undermining the confidentiality of data transmitted over supposedly secure channels. The vulnerability is categorized under CWE-327, which relates to the use of broken or risky cryptographic algorithms. Exploiting this vulnerability does not require authentication or user interaction and can be performed remotely over the network with low attack complexity. The CVSS v2 score is 5.0, reflecting a medium severity impact primarily on confidentiality, with no direct impact on integrity or availability. A patch addressing this vulnerability is available, as referenced in Microsoft Security Bulletin MS98-002. No known exploits in the wild have been reported, but the vulnerability's age and nature suggest that unpatched legacy systems remain at risk. The vulnerability affects a wide range of versions from 0.6.6 through 5.5 of the Stonghold Web Server, indicating a long-standing issue in the product's SSL implementation.

For European organizations, this vulnerability poses a risk to the confidentiality of sensitive data transmitted via affected Stonghold Web Servers using SSL. Although the vulnerability does not affect data integrity or availability, the potential exposure of encrypted session information could lead to data leakage, undermining trust in secure communications. This is particularly critical for sectors handling personal data under GDPR regulations, such as finance, healthcare, and government services. Organizations relying on legacy web server infrastructure that includes Stonghold Web Server versions listed as vulnerable may face compliance risks and reputational damage if sensitive information is compromised. Given the age of the vulnerability, modern deployments are less likely to be affected; however, legacy systems or specialized environments that have not been updated remain vulnerable. The lack of known exploits in the wild reduces immediate threat levels but does not eliminate the risk of targeted attacks exploiting this weakness.

European organizations should conduct an inventory of their web server infrastructure to identify any instances of Stonghold Web Server, particularly legacy versions listed as vulnerable. Immediate mitigation involves applying the official patches referenced in Microsoft Security Bulletin MS98-002 to remediate the PKCS #1 implementation flaw. If patching is not feasible due to legacy system constraints, organizations should consider isolating affected servers from external networks or implementing compensating controls such as network-level encryption (e.g., VPN tunnels) to protect data in transit. Additionally, migrating to modern, actively maintained web server software with up-to-date cryptographic implementations is strongly recommended. Regular security assessments and penetration testing should be conducted to verify the effectiveness of mitigations. Monitoring network traffic for unusual SSL handshake anomalies may help detect attempted exploitation attempts. Finally, organizations should ensure that cryptographic libraries and SSL/TLS configurations adhere to current best practices, avoiding deprecated protocols and weak cipher suites.