CVE-2010-2085 in .NET Framework
Summary
by MITRE
The default configuration of ASP.NET in Microsoft .NET before 1.1 has a value of FALSE for the EnableViewStateMac property, which allows remote attackers to conduct cross-site scripting (XSS) attacks via the __VIEWSTATE parameter.
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Analysis
by VulDB Data Team • 09/14/2021
The vulnerability identified as CVE-2010-2085 represents a critical security flaw in the default configuration of Microsoft .NET Framework versions prior to 1.1, specifically within the ASP.NET implementation. This issue stems from the insecure default setting of the EnableViewStateMac property, which is designed to enable or disable the integrity checking of view state data. When this property is set to FALSE, as it is by default in affected versions, the application becomes susceptible to cross-site scripting attacks that exploit the view state mechanism to inject malicious content into web applications.
The technical exploitation of this vulnerability occurs through manipulation of the __VIEWSTATE parameter, which is a hidden field used by ASP.NET to maintain page state information across postbacks. In vulnerable configurations, attackers can craft malicious view state data that bypasses the normal validation mechanisms, allowing them to inject arbitrary script code that executes in the context of the victim's browser. This occurs because the lack of MAC (Message Authentication Code) validation means that the integrity of the view state data cannot be verified, enabling attackers to modify the serialized state information without detection. The flaw operates at the application layer and specifically targets the ASP.NET framework's state management system, making it particularly dangerous as it can be exploited through normal web browsing activities.
The operational impact of CVE-2010-2085 extends beyond simple XSS attacks, as it provides attackers with a foothold for more sophisticated exploitation techniques that can lead to session hijacking, credential theft, and complete compromise of user sessions. This vulnerability is particularly concerning because it affects the default configuration of ASP.NET applications, meaning that many applications would be vulnerable without explicit security hardening measures. The attack vector requires minimal sophistication and can be executed through standard web browser interactions, making it accessible to attackers with basic web application exploitation knowledge. The vulnerability's presence in the core ASP.NET framework also means that it affects a wide range of applications, from simple web forms to complex enterprise applications that rely on view state management for maintaining user interface state.
Organizations affected by this vulnerability should implement immediate mitigations including explicit setting of the EnableViewStateMac property to TRUE in their web.config files, which enables the integrity checking of view state data and prevents modification attacks. Additionally, comprehensive input validation and output encoding should be implemented throughout the application to provide defense in depth against XSS attacks. The vulnerability aligns with CWE-116, which addresses improper encoding or escaping of output, and relates to ATT&CK technique T1059.007 for command and script injection. Security teams should also consider implementing web application firewalls and monitoring for suspicious view state parameter modifications to detect potential exploitation attempts. Regular security assessments and code reviews should include verification of ASP.NET configuration settings to ensure that security defaults are properly enforced and that applications are not running with vulnerable default configurations that could be exploited by threat actors.