CVE-2009-2505 in Windows
Summary
by MITRE
The Internet Authentication Service (IAS) in Microsoft Windows Vista SP2 and Server 2008 SP2 does not properly validate MS-CHAP v2 Protected Extensible Authentication Protocol (PEAP) authentication requests, which allows remote attackers to execute arbitrary code via crafted structures in a malformed request, aka "Internet Authentication Service Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 09/18/2018
The Internet Authentication Service in Microsoft Windows Vista SP2 and Server 2008 SP2 contains a critical memory corruption vulnerability that arises from improper validation of MS-CHAP v2 Protected Extensible Authentication Protocol authentication requests. This flaw exists within the IAS component that handles network authentication for wireless and wired networks using various authentication methods including PEAP. The vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize and verify the structure of incoming authentication requests, creating an exploitable condition where malformed data can cause memory corruption. The issue is particularly concerning because IAS serves as a central authentication point for network access control, making it a prime target for attackers seeking to compromise network infrastructure. This vulnerability allows remote attackers to execute arbitrary code on the affected systems through carefully crafted authentication requests that exploit memory handling flaws in the authentication processing pipeline.
The technical exploitation of this vulnerability occurs when an attacker sends a malformed MS-CHAP v2 PEAP authentication request to the IAS service. The service processes these requests without adequate validation of the request structure, particularly focusing on the MS-CHAP v2 challenge-response mechanism within the PEAP framework. When the malformed request reaches the IAS service, the insufficient validation causes the authentication processing code to improperly handle memory allocation and data structures, leading to memory corruption. This memory corruption can be leveraged to overwrite critical memory locations, potentially allowing attackers to execute malicious code with the privileges of the IAS service account. The vulnerability is classified as a buffer overflow or memory corruption issue that can be triggered through network-based attacks without requiring authentication, making it particularly dangerous for network infrastructure components. The flaw demonstrates characteristics consistent with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read conditions that can lead to memory corruption.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise entire network authentication infrastructures. Since IAS is commonly used in enterprise environments for wireless network access control, a successful exploitation could provide attackers with unauthorized access to network resources, including access to internal systems, data exfiltration capabilities, and potential lateral movement within the network. The vulnerability affects systems that rely on PEAP authentication, which is widely deployed in corporate networks, educational institutions, and government organizations. Attackers could leverage this vulnerability to establish persistent access points within network infrastructure, potentially bypassing traditional network security controls that depend on proper authentication. The remote nature of the attack means that an attacker could exploit this vulnerability from outside the network perimeter, making it particularly dangerous for organizations that do not properly segment their network infrastructure or implement adequate monitoring of authentication services.
Organizations should implement immediate mitigations including applying Microsoft security updates, implementing network segmentation to isolate IAS services, and deploying network monitoring solutions to detect anomalous authentication traffic patterns. The vulnerability demonstrates the importance of proper input validation and memory safety practices in authentication services, aligning with ATT&CK technique T1566 which covers credential access through social engineering and network-based attacks. Security professionals should also consider implementing network access control lists to restrict access to IAS services, deploying intrusion detection systems that can identify malformed authentication requests, and establishing monitoring protocols for authentication service logs. The vulnerability highlights the need for robust software security practices and proper code review processes, particularly for authentication and authorization services that handle sensitive network access requests. Organizations should also conduct regular vulnerability assessments of their network infrastructure components to identify similar issues that may exist in other authentication services or network protocols. The remediation approach should include not only patching the specific vulnerability but also implementing comprehensive security monitoring and response procedures to detect and respond to similar attacks targeting network authentication infrastructure.