CVE-2009-3103 in Windows
Summary
by MITRE
Array index error in the SMBv2 protocol implementation in srv2.sys in Microsoft Windows Vista Gold, SP1, and SP2, Windows Server 2008 Gold and SP2, and Windows 7 RC allows remote attackers to execute arbitrary code or cause a denial of service (system crash) via an & (ampersand) character in a Process ID High header field in a NEGOTIATE PROTOCOL REQUEST packet, which triggers an attempted dereference of an out-of-bounds memory location, aka "SMBv2 Negotiation Vulnerability." NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/05/2025
The CVE-2009-3103 vulnerability represents a critical array index error within the Server Message Block version 2 protocol implementation in Microsoft Windows operating systems. This flaw exists in the srv2.sys kernel driver component that handles SMBv2 communications, affecting a wide range of Microsoft Windows versions including Vista Gold, SP1, and SP2, Windows Server 2008 Gold and SP2, and Windows 7 RC. The vulnerability stems from inadequate input validation in the processing of SMBv2 NEGOTIATE PROTOCOL REQUEST packets, specifically when handling the Process ID High header field. The flaw manifests when an ampersand character is present in this field, creating a condition where the system attempts to access memory locations outside the bounds of allocated arrays, leading to potential system compromise or instability.
This vulnerability operates at the kernel level within the Windows SMBv2 implementation, making it particularly dangerous as it can be exploited by remote attackers without requiring local system access. The technical flaw constitutes a classic out-of-bounds memory access error that falls under CWE-129, which specifically addresses insufficient checking of array indices. The vulnerability enables attackers to craft malicious SMBv2 packets that trigger memory corruption when the srv2.sys driver processes the malformed NEGOTIATE PROTOCOL REQUEST. When the system encounters the ampersand character in the Process ID High field, it fails to properly validate the input before using it as an array index, resulting in an attempt to dereference memory that was never allocated for that particular access pattern.
The operational impact of CVE-2009-3103 is severe and multifaceted, presenting both remote code execution capabilities and denial of service vulnerabilities. Attackers can leverage this flaw to execute arbitrary code with kernel-level privileges, potentially gaining complete control over affected systems. The vulnerability also enables denial of service attacks that can crash the target system through system crashes or hangs. This makes it particularly attractive for attackers seeking to compromise Windows environments, as it affects multiple widely deployed operating system versions. The vulnerability's remote exploitability means that attackers can target systems without needing physical access or local credentials, making it a significant threat in enterprise environments where SMB services are commonly exposed. Additionally, the vulnerability can be exploited as part of larger attack chains, potentially serving as an initial compromise vector for more sophisticated attacks.
Microsoft addressed this vulnerability through security updates released in October 2009 as part of their regular security bulletin cycle. The fix involved implementing proper input validation in the srv2.sys driver to prevent out-of-bounds memory access when processing SMBv2 NEGOTIATE PROTOCOL REQUEST packets. Organizations should ensure that all affected systems have been patched with the appropriate security updates, particularly since this vulnerability was actively exploited in the wild during its disclosure period. Network administrators should also consider implementing network segmentation and access controls to limit exposure of SMB services to untrusted networks. The vulnerability demonstrates the importance of robust input validation in kernel-level code and highlights the potential for seemingly minor protocol implementation flaws to result in critical security vulnerabilities that can be exploited remotely without authentication. This flaw aligns with ATT&CK technique T1075 by enabling remote code execution and T1499 by providing opportunities for denial of service attacks against critical system services.