CVE-2023-41885 in Piccolo
Summary
by MITRE • 09/13/2023
Piccolo is an ORM and query builder which supports asyncio. In versions 0.120.0 and prior, the implementation of `BaseUser.login` leaks enough information to a malicious user such that they would be able to successfully generate a list of valid users on the platform. As Piccolo on its own does not also enforce strong passwords, these lists of valid accounts are likely to be used in a password spray attack with the outcome being attempted takeover of user accounts on the platform. The impact of this vulnerability is minor as it requires chaining with other attack vectors in order to gain more then simply a list of valid users on the underlying platform. The likelihood of this vulnerability is possible as it requires minimal skills to pull off, especially given the underlying login functionality for Piccolo based sites is open source. This issue has been patched in version 0.121.0.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/10/2023
The CVE-2023-41885 vulnerability affects Piccolo, an asynchronous object-relational mapping library and query builder that supports asyncio operations. This security flaw resides in the BaseUser.login implementation within versions 0.120.0 and earlier, where the authentication mechanism inadvertently exposes information that allows attackers to enumerate valid user accounts on the platform. The vulnerability represents a classic information disclosure issue that undermines the security of authentication systems by providing attackers with actionable intelligence about legitimate user accounts. The flaw specifically manifests during the login process where the system's response behavior differs between valid and invalid user attempts, creating a side-channel information leak that malicious actors can exploit.
The technical implementation of this vulnerability stems from insufficient error handling and response uniformity in the authentication routine. When a user attempts to log in with an invalid username, the system's response differs from when a valid username is provided but an incorrect password is entered. This differential response behavior creates a predictable pattern that attackers can observe and analyze to determine which usernames exist within the system. The vulnerability aligns with CWE-200, Information Exposure, and more specifically with CWE-305, Authentication Bypass Using an Alternate Path or Channel, as it enables unauthorized enumeration of valid accounts without requiring direct authentication attempts against individual accounts. The attack vector leverages the principle of timing differences or response variations that reveal account validity, making it particularly dangerous for systems that do not implement additional security measures.
The operational impact of this vulnerability extends beyond simple account enumeration, as it creates a foundation for more sophisticated attacks such as password spraying campaigns. While the vulnerability itself only provides a list of valid users, it significantly weakens the overall security posture by enabling attackers to target their credential spraying efforts more effectively. The likelihood of exploitation is high given that the vulnerability requires minimal technical skills to identify and exploit, especially since the underlying Piccolo login functionality is publicly available and open source. This makes the attack surface more accessible to threat actors with basic security knowledge, potentially leading to unauthorized account takeovers and subsequent compromise of sensitive data or system resources. The vulnerability's impact is amplified when combined with other attack vectors such as weak password policies, which the CVE description notes as being present in affected systems.
Mitigation strategies for CVE-2023-41885 involve immediate upgrading to Piccolo version 0.121.0 or later, which contains the necessary patches to address the information leakage in the BaseUser.login method. Organizations should also implement additional security controls including rate limiting on authentication attempts, account lockout mechanisms, and robust password policies that enforce strong credentials. The fix addresses the core issue by ensuring that all login attempts return consistent responses regardless of whether the username exists in the system, thereby eliminating the information disclosure channel. Security teams should also consider implementing monitoring for unusual authentication patterns and account enumeration attempts as part of their defensive posture. This vulnerability highlights the importance of consistent error handling in authentication systems and demonstrates how seemingly minor implementation flaws can create significant security risks when combined with other attack vectors. The remediation aligns with ATT&CK technique T1110.003, Brute Force: Password Spraying, by addressing the initial reconnaissance phase that enables such attacks to be more effective.