CVE-2000-0979 in Windows
Summary
by MITRE
File and Print Sharing service in Windows 95, Windows 98, and Windows Me does not properly check the password for a file share, which allows remote attackers to bypass share access controls by sending a 1-byte password that matches the first character of the real password, aka the "Share Level Password" vulnerability.
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Analysis
by VulDB Data Team • 10/12/2025
The CVE-2000-0979 vulnerability represents a critical authentication flaw in the Windows 95 98 and Me operating systems that fundamentally undermines the security of file and print sharing services. This vulnerability specifically targets the share-level authentication mechanism where the system fails to properly validate password length and complexity, creating a significant security gap that attackers can exploit to gain unauthorized access to network resources.
The technical flaw in this vulnerability stems from the implementation of the Server Message Block protocol where the system performs a rudimentary password validation that only checks the first character of a password against the actual stored password. This design flaw allows an attacker to craft a 1-byte password that matches the first character of the legitimate password, thereby bypassing the authentication process entirely. The vulnerability is classified under CWE-287 which addresses improper certificate validation and authentication mechanisms, and aligns with ATT&CK technique T1110.001 for credential access through password guessing and brute force attacks.
The operational impact of this vulnerability is severe as it enables remote attackers to access shared files and printers without proper authorization, potentially leading to data theft, system compromise, and lateral movement within networks. Attackers can exploit this weakness to gain persistent access to sensitive information, disrupt business operations, and establish footholds for further attacks. The vulnerability affects systems that rely on share-level authentication, making it particularly dangerous in environments where legacy systems are still operational.
Mitigation strategies for this vulnerability include implementing immediate patches from Microsoft that address the authentication flaw, disabling unnecessary file and print sharing services, and enforcing stronger authentication mechanisms such as user-level authentication instead of share-level authentication. Organizations should also consider network segmentation to limit access to critical systems, implement proper firewall rules to restrict SMB traffic, and conduct comprehensive vulnerability assessments to identify and remediate similar authentication weaknesses. The vulnerability serves as a critical reminder of the importance of proper authentication design and the dangers of legacy system security flaws that persist across multiple operating system versions.