CVE-2003-0907 in Windows
Summary
by MITRE
Help and Support Center in Microsoft Windows XP SP1 does not properly validate HCP URLs, which allows remote attackers to execute arbitrary code via quotation marks in an hcp:// URL, which are not quoted when constructing the argument list to HelpCtr.exe.
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Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2003-0907 represents a critical buffer overflow flaw within the Help and Support Center component of Microsoft Windows XP Service Pack 1. This security weakness specifically affects the HCP URL handling mechanism that processes help requests through the HelpCtr.exe application. The vulnerability stems from inadequate input validation when processing HCP URLs, creating an exploitable condition that can be leveraged by remote attackers to execute arbitrary code on affected systems. The flaw manifests when quotation marks within hcp:// URLs are not properly escaped or quoted during argument list construction, leading to improper command line argument handling.
This vulnerability operates at the application level within the Windows XP operating system and directly impacts the Help and Support Center functionality. The technical implementation flaw occurs in the HelpCtr.exe executable which receives HCP URLs as input parameters. When these URLs contain quotation marks, the system fails to properly sanitize or escape these special characters before constructing command line arguments. This improper handling results in a classic buffer overflow condition where attacker-controlled data can overwrite adjacent memory locations, potentially allowing code execution with the privileges of the HelpCtr.exe process. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a command injection vulnerability that enables arbitrary code execution.
The operational impact of this vulnerability is severe as it allows remote attackers to execute malicious code on Windows XP systems without requiring local access or authentication. Attackers can craft specially formatted HCP URLs containing quotation marks that, when processed by the vulnerable HelpCtr.exe application, trigger the buffer overflow condition. This creates a significant attack surface since the Help and Support Center is typically accessible through various network-based interfaces and can be triggered through web browser navigation or other applications that utilize HCP URL schemes. The exploitation can lead to complete system compromise, privilege escalation, and potential lateral movement within network environments where Windows XP systems are deployed.
Mitigation strategies for this vulnerability include applying the official Microsoft security patch released as part of Windows XP Service Pack 2 and subsequent updates. Organizations should also implement network-based restrictions to limit access to Help and Support Center functionality, particularly when processing untrusted HCP URLs. Security configurations should enforce proper input validation and sanitization for all URL processing components, ensuring that special characters including quotation marks are properly escaped or quoted during argument construction. System administrators should consider disabling unnecessary help center functionality and implementing application whitelisting policies to prevent unauthorized execution of HelpCtr.exe with malicious arguments. This vulnerability demonstrates the importance of proper input validation and command line argument handling, aligning with ATT&CK technique T1059.007 for command and script interpreter execution, and highlights the critical need for robust sanitization of user-supplied data in system components.