Patch Issued for W2K Domain Controller Memory Leak
- By Scott Bekker
- May 09, 2001
A vulnerability in Windows 2000 can allow internal and external attackers to take down domain controllers, according to a security bulletin Microsoft Corp. sent out late Tuesday.
A Swedish Internet security firm called Defcom reported the issue to Microsoft and helped with the fix.
“A core service running on Windows 2000 domain controllers contains a memory leak, which can be triggered when it attempts to process a certain type of invalid service request,” Microsoft’s security bulletin reads. Because it is a core service for a domain controller, it cannot be disabled to guard against the problem.
To exploit the vulnerability, an attacker would send the invalid requests repeatedly to deplete available memory on the server. The attack could make the domain controller unresponsive for processing logon requests or issuing new Kerberos tickets.
Rebooting fixes the problem, Microsoft points out, and the company maintains that normal security practices such as deploying firewalls should prevent the external users from sending requests to domain controllers. However, the vulnerability could still be exploited from within a corporate network.
The vulnerability affects Windows 2000 Server, Windows 2000 Advanced Server and Windows 2000 Datacenter Server computers running as domain controllers, but does not affect Windows NT 4.0 servers.
Microsoft plans to roll the fix into Windows 2000 Service Pack 3.
Microsoft’s security bulletin, its 24th this year, can be found here. –
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Scott Bekker is editor in chief of Redmond Channel Partner magazine.