CVE-1999-1277 is a vulnerability found in the BackWeb client software, specifically related to how it handles proxy authentication credentials. The BackWeb client stores the username and password in cleartext within the Communication registry key on the local system. This insecure storage method means that any local user with access to the machine can read these credentials directly from the registry without needing elevated privileges or authentication. The vulnerability arises because the sensitive authentication data is not encrypted or obfuscated, exposing it to potential misuse. An attacker who obtains these credentials could impersonate the legitimate user to access proxy services or other network resources that rely on these credentials. The CVSS score of 4.6 (medium severity) reflects that the attack vector is local (AV:L), with low attack complexity (AC:L), no authentication required (Au:N), and partial impact on confidentiality, integrity, and availability (C:P/I:P/A:P). Since this vulnerability dates back to 1998 and no patches are available, it indicates that the product is likely obsolete or unsupported. There are no known exploits in the wild, but the risk remains for environments still using this software. The vulnerability primarily affects the confidentiality and integrity of proxy authentication credentials on affected systems.

For European organizations, the impact of this vulnerability depends on whether BackWeb client software is still in use within their environments. If present, the cleartext storage of proxy credentials could allow an insider or any local attacker to escalate privileges by leveraging stolen credentials to access proxy services or internal networks. This could lead to unauthorized access to sensitive data, interception of network traffic, or lateral movement within the organization. Given the local attack vector, the threat is more relevant in environments where multiple users share systems or where endpoint security is weak. Although the vulnerability does not directly enable remote exploitation, the compromise of proxy credentials can facilitate further attacks, potentially affecting confidentiality and integrity of communications. European organizations with legacy systems or those in sectors with less frequent software updates (such as industrial or governmental entities) might be more vulnerable. The lack of patch availability means organizations must rely on compensating controls to mitigate risk.

Since no patch is available for this vulnerability, European organizations should focus on compensating controls to reduce risk. First, identify and inventory any systems running the BackWeb client and assess their necessity; consider decommissioning or replacing the software with modern, supported alternatives that securely handle credentials. Restrict local user access on affected systems to trusted personnel only, employing strict access controls and user account management to minimize the risk of unauthorized local access. Employ endpoint security solutions that monitor and alert on suspicious registry access or credential dumping attempts. Encrypt sensitive data at rest where possible and use OS-level protections to restrict registry key permissions, ensuring only system administrators can read the Communication registry key. Additionally, implement network segmentation to limit the impact of compromised proxy credentials and monitor proxy authentication logs for unusual activity. Regularly educate users and administrators about the risks of credential exposure and enforce strong password policies to reduce the impact of credential theft.