Microsoft Windows 2000 Domain Account Lockout Bypass Vulnerability
BID:1973
Info
Microsoft Windows 2000 Domain Account Lockout Bypass Vulnerability
| Bugtraq ID: | 1973 |
| Class: | Access Validation Error |
| CVE: | |
| Remote: | Yes |
| Local: | Yes |
| Published: | Nov 21 2000 12:00AM |
| Updated: | Nov 21 2000 12:00AM |
| Credit: | Discovered by Brett Finch <[email protected]> and publicized in a Microsoft Security Bulletin (MS00-089) on November 21, 2000. |
| Vulnerable: |
Microsoft Windows 2000 Server SP1 Microsoft Windows 2000 Professional SP1 Microsoft Windows 2000 Advanced Server SP1 |
| Not Vulnerable: | |
Discussion
Microsoft Windows 2000 Domain Account Lockout Bypass Vulnerability
Under certain circumstances, it is possible to bypass a domain account lockout policy on a local machine which would render this protective measure against brute force password attempts ineffective. The purpose of a domain account lockout policy is to disable an account after a certain number of unsuccessful login attempts. If this policy was not implemented, the password of a domain account could be guessed an unlimited number of times.
Windows 2000 hosts in a non-2000 domain using NTLM authentication will fail to recognize a domain account lockout policy for users whose credentials are locally cached. Cached credentials contain the username and password in hashed form and are used in the event that the domain controller is not available to perform authentication. Windows 2000 systems that are not using NTLM to perform authentication are not susceptible to this vulnerability, therefore clients that are members of Windows 2000 domains would not be vulnerable because Kerberos authentication is being implemented.
This vulnerability would allow for the possibility of successful retrieval of a valid password through the use of brute force techniques. If a malicious user was able to login with a password acquired from a brute force attack, they would gain privileges of the same level as the domain account but would be confined to the local machine because domain authentication would not be able to take place and the lockout policy would be exercised at the domain level.
Under certain circumstances, it is possible to bypass a domain account lockout policy on a local machine which would render this protective measure against brute force password attempts ineffective. The purpose of a domain account lockout policy is to disable an account after a certain number of unsuccessful login attempts. If this policy was not implemented, the password of a domain account could be guessed an unlimited number of times.
Windows 2000 hosts in a non-2000 domain using NTLM authentication will fail to recognize a domain account lockout policy for users whose credentials are locally cached. Cached credentials contain the username and password in hashed form and are used in the event that the domain controller is not available to perform authentication. Windows 2000 systems that are not using NTLM to perform authentication are not susceptible to this vulnerability, therefore clients that are members of Windows 2000 domains would not be vulnerable because Kerberos authentication is being implemented.
This vulnerability would allow for the possibility of successful retrieval of a valid password through the use of brute force techniques. If a malicious user was able to login with a password acquired from a brute force attack, they would gain privileges of the same level as the domain account but would be confined to the local machine because domain authentication would not be able to take place and the lockout policy would be exercised at the domain level.
Exploit / POC
Microsoft Windows 2000 Domain Account Lockout Bypass Vulnerability
See discussion.
See discussion.
Solution / Fix
Microsoft Windows 2000 Domain Account Lockout Bypass Vulnerability
Solution:
Microsoft has released the following patch which eliminates this vulnerability:
Microsoft Windows 2000 Server SP1
Microsoft Windows 2000 Advanced Server SP1
Microsoft Windows 2000 Professional SP1
Solution:
Microsoft has released the following patch which eliminates this vulnerability:
Microsoft Windows 2000 Server SP1
-
Microsoft Q274372
http://download.microsoft.com/download/win2000platform/Patch/q274372/N T5/EN-US/Q274372_W2K_SP2_x86_en.EXE
Microsoft Windows 2000 Advanced Server SP1
-
Microsoft Q274372
http://download.microsoft.com/download/win2000platform/Patch/q274372/N T5/EN-US/Q274372_W2K_SP2_x86_en.EXE
Microsoft Windows 2000 Professional SP1
References
Microsoft Windows 2000 Domain Account Lockout Bypass Vulnerability
References:
References: