CVE-2022-38755 is a security vulnerability identified in Micro Focus Filr, a file sharing and collaboration platform widely used by enterprises to facilitate secure file access and sharing across devices and locations. The vulnerability affects versions prior to 4.3.1.1 and allows a remote, unauthenticated attacker to perform user enumeration. Specifically, an attacker can remotely query the system to determine which usernames are valid without needing any authentication or user interaction. This is typically achieved by analyzing differences in system responses or error messages when submitting various usernames, enabling attackers to compile a list of legitimate users. Although this vulnerability does not directly allow access to files or system control, it leaks sensitive information about user accounts that can be leveraged in subsequent attacks such as brute force password guessing, phishing, or social engineering. The CVSS 3.1 base score is 5.3 (medium severity), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and impacts confidentiality (C:L) but not integrity or availability. No known exploits in the wild have been reported to date, and no specific patch links were provided, but upgrading to version 4.3.1.1 or later is implied as the remediation. The vulnerability's impact is limited to information disclosure of valid usernames, which can be a critical first step in targeted attacks against organizations using Micro Focus Filr for file collaboration and storage.

For European organizations, this vulnerability poses a moderate risk primarily through the exposure of valid user accounts. Organizations relying on Micro Focus Filr for sensitive document sharing, especially in regulated sectors such as finance, healthcare, and government, could face increased risk of targeted credential-based attacks. User enumeration can facilitate brute force or credential stuffing attacks, potentially leading to unauthorized access if combined with weak or reused passwords. Additionally, knowledge of valid usernames can enhance the effectiveness of phishing campaigns tailored to specific employees, increasing the likelihood of successful social engineering. While the vulnerability does not directly compromise file integrity or availability, the indirect risks to confidentiality and subsequent attack vectors could lead to data breaches or compliance violations under GDPR and other European data protection laws. The impact is heightened in environments where multi-factor authentication (MFA) is not enforced or where user account monitoring is insufficient.

To mitigate this vulnerability, European organizations should prioritize upgrading Micro Focus Filr installations to version 4.3.1.1 or later where the issue is resolved. In parallel, implement strict monitoring and alerting on authentication endpoints to detect unusual enumeration patterns or repeated login attempts. Deploy rate limiting and IP blacklisting to hinder automated enumeration attempts. Enforce strong password policies and mandate multi-factor authentication (MFA) for all users to reduce the risk of credential compromise following enumeration. Additionally, review and harden error message handling in the application to ensure uniform responses that do not reveal user existence information. Conduct regular security awareness training to help users recognize and report phishing attempts that may exploit enumerated usernames. Finally, consider network segmentation and access controls to limit exposure of the Filr service to trusted networks or VPN users only, reducing the attack surface.