CVE-2011-3416 in .NET Framework
Summary
by MITRE
The Forms Authentication feature in the ASP.NET subsystem in Microsoft .NET Framework 1.1 SP1, 2.0 SP2, 3.5 SP1, 3.5.1, and 4.0 allows remote authenticated users to obtain access to arbitrary user accounts via a crafted username, aka "ASP.Net Forms Authentication Bypass Vulnerability."
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Analysis
by VulDB Data Team • 03/20/2021
The CVE-2011-3416 vulnerability represents a critical authentication bypass flaw within Microsoft's ASP.NET framework that affects multiple versions including .NET Framework 1.1 SP1 through 4.0. This vulnerability specifically targets the Forms Authentication mechanism, which is a fundamental component of web application security that manages user authentication and session handling. The flaw allows authenticated attackers to manipulate the authentication process by crafting specially formatted usernames, potentially gaining unauthorized access to other user accounts within the system. This type of vulnerability falls under the category of authentication bypass attacks that can severely compromise the security posture of web applications relying on ASP.NET forms authentication.
The technical root cause of this vulnerability stems from improper validation of user input within the Forms Authentication subsystem. When processing authentication requests, the ASP.NET framework fails to adequately sanitize or validate the username parameter, allowing maliciously crafted input to bypass normal authentication checks. The vulnerability specifically manifests when the system processes usernames that contain certain special characters or sequences that manipulate the internal authentication logic. This flaw enables attackers to construct usernames that, when processed by the authentication system, result in the system incorrectly granting access to accounts other than the one specified in the login attempt. The vulnerability can be classified under CWE-287, which deals with Improper Handling of Authentication Credentials, and aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.001 for Phishing.
The operational impact of CVE-2011-3416 is substantial as it allows remote attackers to escalate privileges and access unauthorized user accounts without proper credentials. This vulnerability can be exploited by authenticated users who have access to the application, making it particularly dangerous in environments where users have legitimate access to the system. Attackers can leverage this flaw to impersonate other users, potentially accessing sensitive data, performing unauthorized transactions, or conducting further attacks within the compromised application. The vulnerability affects the core authentication mechanism of web applications, which means that any application relying on ASP.NET Forms Authentication is at risk. The impact extends beyond individual account compromise to potentially enable broader system infiltration and data breaches.
Mitigation strategies for CVE-2011-3416 require immediate implementation of Microsoft security patches and updates to affected .NET Framework versions. Organizations should apply the relevant security updates from Microsoft to address the underlying authentication bypass vulnerability. Additionally, implementing proper input validation and sanitization measures can help prevent exploitation of similar vulnerabilities in the future. Security configurations should include restrictions on special character usage in authentication parameters and enhanced monitoring of authentication attempts. Organizations should also consider implementing multi-factor authentication as an additional security layer and regularly audit authentication logs for suspicious activity. The vulnerability demonstrates the importance of proper credential handling and input validation in web application security, aligning with security best practices outlined in frameworks such as NIST SP 800-53 and ISO 27001. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar authentication-related flaws in web applications.