CVE-2010-2731 in IIS
Summary
by MITRE
Unspecified vulnerability in Microsoft Internet Information Services (IIS) 5.1 on Windows XP SP3, when directory-based Basic Authentication is enabled, allows remote attackers to bypass intended access restrictions and execute ASP files via a crafted request, aka "Directory Authentication Bypass Vulnerability."
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Analysis
by VulDB Data Team • 08/31/2024
The vulnerability described in CVE-2010-2731 represents a critical authentication bypass flaw within Microsoft Internet Information Services version 5.1 running on Windows XP Service Pack 3. This issue specifically targets the directory-based Basic Authentication mechanism, which is a fundamental security feature designed to control access to web resources. The flaw enables remote attackers to circumvent intended access controls and execute Active Server Pages files without proper authentication credentials. This represents a significant weakness in the web server's security architecture, as it undermines the core principle of access control that Basic Authentication is meant to enforce.
The technical implementation of this vulnerability stems from improper handling of authentication requests when directory-based Basic Authentication is enabled in IIS 5.1. When a client makes a request to a protected directory, the server should validate credentials before granting access to ASP files or other resources. However, the flaw in the authentication processing allows attackers to craft specific requests that bypass this validation mechanism entirely. The vulnerability specifically affects systems where Basic Authentication is configured at the directory level, making it particularly dangerous for web applications that rely on this authentication method to protect sensitive content and executable scripts. This issue falls under the CWE-284 category of Improper Access Control, which encompasses weaknesses that allow unauthorized access to resources due to insufficient access restriction mechanisms.
The operational impact of this vulnerability is severe and far-reaching for affected organizations. Attackers can exploit this flaw to gain unauthorized access to web applications hosted on vulnerable IIS servers, potentially leading to complete system compromise. The ability to execute ASP files without proper authentication opens the door to various malicious activities including data theft, system modification, and deployment of malware. This vulnerability is particularly dangerous because it can be exploited remotely without requiring any prior authentication or special privileges, making it an attractive target for automated attacks. The attack surface is broad as any organization running IIS 5.1 with directory-based Basic Authentication enabled is potentially at risk, especially in environments where legacy systems have not been properly updated or patched. This vulnerability aligns with ATT&CK technique T1210 - Exploitation of Remote Services, as it represents a remote exploitation vector that leverages authentication bypass to gain access to systems.
Mitigation strategies for CVE-2010-2731 should prioritize immediate patching of affected systems with Microsoft security updates. Organizations should disable directory-based Basic Authentication where possible and implement alternative authentication mechanisms such as Windows Authentication or form-based authentication. Network segmentation and firewall rules should be implemented to limit access to vulnerable web servers, while monitoring systems should be deployed to detect suspicious authentication patterns. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all instances of IIS 5.1 in their environment and ensure proper configuration of authentication settings. The remediation process should include not only applying the necessary security patches but also reviewing and strengthening overall web server security configurations. This vulnerability demonstrates the critical importance of maintaining up-to-date security measures and proper authentication configuration management as outlined in security frameworks such as NIST SP 800-53 and ISO 27001 controls related to access control and vulnerability management.