CVE-2001-1238 in Windows
Summary
by MITRE
Task Manager in Windows 2000 does not allow local users to end processes with uppercase letters named (1) winlogon.exe, (2) csrss.exe, (3) smss.exe and (4) services.exe via the Process tab which could allow local users to install Trojan horses that cannot be stopped with the Task Manager.
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability described in CVE-2001-1238 represents a significant security flaw in the Windows 2000 operating system's Task Manager implementation. This issue specifically affects the process termination functionality within the Task Manager's Process tab, creating a dangerous privilege escalation vector for local attackers. The vulnerability stems from an inconsistent case-sensitive handling of process names during the termination process, where the system fails to properly match process identifiers when uppercase letters are used in the process names. This fundamental design flaw allows malicious actors to create processes with uppercase names that bypass the normal Task Manager termination controls, effectively creating persistent backdoors that cannot be removed through standard administrative means.
The technical implementation of this vulnerability exploits a classic input validation weakness that falls under the CWE-691 category of Insufficient Control Flow Management. The flaw manifests when local users create processes named with uppercase letters such as WINLOGON.EXE, CSRSS.EXE, SMSS.EXE, and SERVICES.EXE, which are critical system processes. The Task Manager's internal matching algorithm fails to properly normalize the case of process names during comparison operations, allowing these malicious processes to evade termination attempts. This behavior creates a persistent threat surface where attackers can establish malicious processes that remain immune to standard task management controls, effectively disabling the operating system's built-in process termination capabilities. The vulnerability directly impacts the principle of least privilege and undermines the operating system's core security model by allowing unauthorized process manipulation.
The operational impact of CVE-2001-1238 extends far beyond simple process management disruption, creating a persistent security risk that aligns with several tactics described in the MITRE ATT&CK framework under the T1059.001 and T1068 categories for process injection and privilege escalation. Local users can leverage this vulnerability to install Trojan horses, rootkits, or other malicious software that remains undetectable through standard Task Manager operations. The inability to terminate these processes through conventional means provides attackers with a reliable method for maintaining persistence on compromised systems. This vulnerability essentially creates a backdoor mechanism that allows attackers to maintain control over the system without requiring elevated privileges or complex exploitation techniques, making it particularly dangerous in enterprise environments where local user access may be more prevalent than anticipated.
Security mitigations for this vulnerability should focus on both immediate system hardening and long-term architectural improvements. System administrators should implement strict process monitoring and alerting mechanisms to detect unusual process creation patterns, particularly those involving system-critical processes with uppercase naming conventions. The most effective immediate solution involves applying the relevant Microsoft security patches that address the case sensitivity handling in Task Manager's process termination logic. Organizations should also consider implementing additional process control measures such as application whitelisting, mandatory access controls, and comprehensive audit logging of process creation and termination events. From a defensive perspective, this vulnerability highlights the importance of proper input normalization and case handling in security-critical applications, emphasizing the need for robust security testing that includes edge cases and unusual input scenarios to prevent similar flaws in future software implementations.