CVE-2005-0551 in Windows
Summary
by MITRE
Stack-based buffer overflow in WINSRV.DLL in the Client Server Runtime System (CSRSS) process of Microsoft Windows 2000, Windows XP SP1 and SP2, and Windows Server 2003 allows local users to gain privileges via a specially-designed application that provides console window information with a long FaceName value.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/05/2025
The vulnerability described in CVE-2005-0551 represents a critical stack-based buffer overflow within the Windows Client Server Runtime System component, specifically affecting WINSRV.DLL in the CSRSS process. This flaw exists in multiple Microsoft Windows operating systems including Windows 2000, Windows XP Service Pack 1 and 2, and Windows Server 2003. The vulnerability stems from improper input validation within the console window management subsystem where the FaceName parameter is processed without adequate bounds checking. The FaceName value represents the font name used for console windows, and when this parameter exceeds the allocated buffer size, it results in a classic stack overflow condition that can be exploited by malicious applications.
The technical implementation of this vulnerability involves the CSRSS process which serves as a critical system component responsible for managing console windows and other user interface elements for Windows applications. When a specially crafted application attempts to create a console window with an excessively long FaceName parameter, the WINSRV.DLL module fails to validate the input length before copying it into a fixed-size stack buffer. This buffer overflow condition allows an attacker to overwrite adjacent memory locations including return addresses and stack canaries, potentially enabling arbitrary code execution. The vulnerability specifically targets the stack memory layout of the CSRSS process, which operates with elevated privileges due to its system-level nature. This creates a privilege escalation vector where local users can leverage the overflow to execute code with system-level privileges, bypassing standard user access controls.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it represents a fundamental weakness in Windows kernel security architecture that can be exploited by malicious applications or malware running in the local context. Attackers can craft applications that deliberately trigger the buffer overflow condition to gain unauthorized access to system resources, potentially leading to complete system compromise. The vulnerability affects systems where users can execute applications locally, making it particularly dangerous in multi-user environments where untrusted applications might be run. The exploitability of this vulnerability is enhanced by the fact that it requires no network connectivity, as the attack vector operates entirely within the local system context, making it difficult to detect through traditional network monitoring tools.
Mitigation strategies for CVE-2005-0551 should focus on both immediate patching and operational security measures. Microsoft released security updates for all affected Windows versions that address the buffer overflow condition through proper input validation and bounds checking in the WINSRV.DLL module. Organizations should prioritize deployment of these patches across all affected systems, particularly in environments where untrusted applications might be executed. Additionally, implementing application whitelisting policies can prevent malicious applications from executing and triggering the vulnerability. System administrators should also consider disabling unnecessary console window functionality where possible, as this reduces the attack surface for exploitation. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in software security, and represents a technique commonly associated with privilege escalation attacks in the MITRE ATT&CK framework under the Privilege Escalation tactic. Organizations should also implement regular security assessments and vulnerability scanning to identify systems that may not have received the necessary patches, as this vulnerability has remained relevant in various security contexts since its initial disclosure.