CVE-2022-31177 is a medium-severity vulnerability identified in the Flask-AppBuilder framework, versions prior to 4.1.3. Flask-AppBuilder is a popular application development framework built on top of the Flask Python framework, widely used for building web applications with integrated user management and role-based access control. The vulnerability arises from an information exposure issue (CWE-200) where an authenticated administrator user can query other users by their salted and hashed password strings using partial hash fragments. Although the actual hashed passwords are not directly returned in the query responses, the ability to filter and infer partial password hashes linked to specific user accounts can aid an attacker in gathering sensitive authentication-related information. This leakage could potentially facilitate offline password cracking attempts or targeted attacks against user credentials. The flaw requires the attacker to have authenticated admin-level access, limiting the initial attack surface to insiders or compromised admin accounts. The issue was resolved in Flask-AppBuilder version 4.1.3, and users are strongly advised to upgrade to this or later versions. No known workarounds exist, and no exploits have been reported in the wild to date. The vulnerability was publicly disclosed on August 1, 2022, and has been enriched with CISA data, indicating recognition by US cybersecurity authorities.

For European organizations, the exposure of partial password hashes linked to user accounts can have significant security implications, particularly in environments where Flask-AppBuilder is used to manage sensitive applications or data. Although the vulnerability requires admin authentication, if an attacker gains such access through credential compromise, phishing, or insider threat, they could leverage this flaw to extract partial password hashes. This information could be used to perform offline brute-force or dictionary attacks to recover user passwords, potentially leading to further unauthorized access, privilege escalation, or lateral movement within the network. The impact on confidentiality is moderate, as direct password hashes are not exposed but partial hashes can aid attackers. Integrity and availability impacts are indirect but possible if attackers use recovered credentials to manipulate data or disrupt services. Given the framework’s use in various sectors including healthcare, finance, and government services across Europe, exploitation could lead to data breaches, regulatory non-compliance (e.g., GDPR violations), and reputational damage. The absence of known exploits reduces immediate risk, but the vulnerability remains a concern for organizations with exposed or poorly secured admin interfaces.

1. Immediate upgrade to Flask-AppBuilder version 4.1.3 or later is the most effective mitigation to eliminate the vulnerability. 2. Restrict and monitor admin-level access rigorously, employing strong multi-factor authentication (MFA) to reduce the risk of credential compromise. 3. Implement network segmentation and access controls to limit exposure of admin interfaces to trusted networks and users only. 4. Conduct regular audits of admin account activities and review logs for suspicious queries or access patterns that could indicate exploitation attempts. 5. Employ password policies enforcing strong, unique passwords and consider using password hashing algorithms with high computational cost (e.g., bcrypt, Argon2) to reduce the feasibility of offline cracking. 6. If upgrading is temporarily not possible, consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block suspicious query patterns targeting password hashes. 7. Educate administrators on the risks of this vulnerability and the importance of safeguarding their credentials and sessions. 8. Integrate vulnerability scanning and continuous monitoring to detect outdated Flask-AppBuilder versions in the environment.