CVE-2000-0851 in Windows
Summary
by MITRE
Buffer overflow in the Still Image Service in Windows 2000 allows local users to gain additional privileges via a long WM_USER message, aka the "Still Image Service Privilege Escalation" vulnerability.
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Analysis
by VulDB Data Team • 04/02/2025
The CVE-2000-0851 vulnerability represents a critical buffer overflow flaw within the Still Image Service component of Microsoft Windows 2000 operating systems. This service handles communication with imaging devices and processes Windows messages through the WM_USER message queue mechanism. The vulnerability specifically manifests when the service receives a malformed WM_USER message containing an excessively long payload that exceeds the allocated buffer space. This buffer overflow condition occurs in the service's message handling routine where insufficient input validation and bounds checking fail to prevent the overflow scenario.
The technical exploitation of this vulnerability leverages the inherent privilege structure of Windows 2000 systems where the Still Image Service typically runs with elevated privileges. When a local user crafts and sends a specially constructed WM_USER message with an oversized payload, the buffer overflow corrupts adjacent memory locations and potentially allows the attacker to overwrite critical program execution pointers or control structures. This memory corruption can be manipulated to redirect execution flow and ultimately elevate the user's privileges from standard user level to SYSTEM level access. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which represents a fundamental weakness in memory management and input validation practices.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise for local attackers. Since the vulnerability requires only local access to exploit, it can be leveraged by any user with login privileges on the affected system. This makes it particularly dangerous in multi-user environments where attackers might gain initial access through social engineering or other means and then escalate their privileges to achieve full system control. The Still Image Service is often enabled by default in Windows 2000 installations, making this vulnerability widely exploitable across affected systems. The attack vector is particularly insidious because it operates at the service level rather than requiring kernel-level exploitation, making detection more difficult for traditional security monitoring systems.
Mitigation strategies for CVE-2000-0851 should focus on both immediate remediation and long-term security hardening measures. Microsoft addressed this vulnerability through security patches released in 2000, but organizations should ensure all Windows 2000 systems are properly updated with the latest security updates. System administrators should disable unnecessary services including the Still Image Service if it is not required for business operations. Additionally, implementing proper input validation and bounds checking mechanisms within application code can prevent similar buffer overflow conditions. The vulnerability aligns with ATT&CK technique T1068 which covers privilege escalation through local exploits, and T1059 which encompasses command and scripting interpreter usage. Network segmentation and least privilege access controls should be implemented to limit the potential impact of successful exploitation, while regular security assessments should be conducted to identify similar vulnerabilities in legacy systems that may still be operational in enterprise environments.