CVE-2010-1256 in IIS
Summary
by MITRE
Unspecified vulnerability in Microsoft IIS 6.0, 7.0, and 7.5, when Extended Protection for Authentication is enabled, allows remote authenticated users to execute arbitrary code via unknown vectors related to "token checking" that trigger memory corruption, aka "IIS Authentication Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 01/26/2025
Microsoft IIS versions 6.0, 7.0, and 7.5 contain a critical memory corruption vulnerability that manifests when Extended Protection for Authentication is enabled. This vulnerability resides in the token checking mechanism used during authentication processes and affects remote authenticated users who can leverage specific conditions to trigger memory corruption. The flaw occurs during the validation of authentication tokens, where improper handling of token data can lead to buffer overflows or other memory corruption conditions that may be exploited to execute arbitrary code on the affected system. The vulnerability represents a significant security risk as it allows authenticated attackers to potentially escalate privileges or gain full system control. From a cybersecurity perspective, this issue aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions. The vulnerability's exploitation pathway through token checking mechanisms also relates to ATT&CK technique T1550.001 for valid accounts and T1070.004 for indicator removal, as attackers may attempt to establish persistent access through compromised authentication tokens. The memory corruption occurs within the authentication subsystem where token validation routines fail to properly check bounds during token processing, creating opportunities for attackers to craft malicious tokens that cause memory corruption. This vulnerability demonstrates the complexity of authentication token handling in web servers and the potential for subtle flaws in cryptographic validation routines to create severe security implications. The impact extends beyond simple code execution to potentially allow attackers to bypass security controls and access sensitive system resources.
The technical implementation of this vulnerability involves the interaction between Extended Protection for Authentication and the underlying token validation infrastructure. When Extended Protection is enabled, IIS performs additional authentication checks that involve processing authentication tokens through memory structures that do not properly validate token boundaries. The flaw specifically manifests in the token checking code path where authentication token data is processed without adequate buffer size validation. Attackers can leverage this by crafting specially formatted authentication tokens that trigger memory corruption during the validation process, potentially leading to code execution with the privileges of the IIS service account. The vulnerability's nature as a memory corruption issue places it within the category of heap-based buffer overflows, where attacker-controlled data is written beyond allocated memory boundaries. This type of vulnerability is particularly dangerous because it can be exploited to execute arbitrary code, potentially allowing full system compromise. The authentication context provides a legitimate access path that makes exploitation more feasible compared to other memory corruption vulnerabilities that require additional attack vectors.
Organizations running affected IIS versions must implement immediate mitigations to address this vulnerability. The primary recommendation involves disabling Extended Protection for Authentication when it is not strictly required, as this eliminates the vulnerable code path entirely. Microsoft released security updates that address the underlying memory corruption issue in the authentication token processing routines, and organizations should apply these patches promptly. Additionally, network segmentation and access controls should be implemented to limit the potential impact of exploitation, as authenticated access is required to exploit this vulnerability. Security monitoring should focus on unusual authentication patterns and token processing activities that might indicate exploitation attempts. The vulnerability's characteristics make it particularly susceptible to exploitation by attackers who have already gained some level of authentication access, making proper access controls and monitoring essential components of the defense strategy. System administrators should also consider implementing application whitelisting and other runtime protections to limit the potential impact of successful exploitation attempts. The remediation approach should include comprehensive testing of patches in controlled environments before deployment to ensure compatibility with existing applications and services. Organizations should also review their authentication policies and implement least privilege principles to minimize the potential damage from successful exploitation attempts.