Security Bulletin MS01-040

2001-07-26T00:00:00
ID SECURITYVULNS:DOC:1876
Type securityvulns
Reporter Securityvulns
Modified 2001-07-26T00:00:00

Description


Title: Invalid RDP Data Can Cause Memory Leak in Terminal Services Date: 25 July 2001 Software: Windows 2000 Server and Windows NT 4.0, Terminal Server Edition Impact: Denial of Service Bulletin: MS01-040

Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS01-040.asp.


Issue:

The Windows 2000 Terminal Service and Windows NT 4.0 Terminal Server Edition contains a memory leak in one of the functions that processes incoming Remote Data Protocol data via port 3389. Each time an RDP packet containing a specific type of malformation is processed, the memory leak depletes overall server memory by a small amount.

If an attacker sent a sufficiently large quantity of such data to an affected machine, he could deplete the machine's memory to the point where response time would be slowed or the machine's ability to respond would be stopped altogether. All system services would be affected, including but not limited to terminal services. Normal operation could be restored by rebooting the machine.

Mitigating Factors:

  • Normal firewalling could be used to prevent an attacker from exploiting this vulnerability from the Internet. Specifically, blocking port 3389 would prevent an attacker from delivering data to the affected service, thereby preventing him from exploiting the vulnerability.

  • There is no capability to compromise data or usurp privileges via the vulnerability.

Patch Availability:

  • A patch is available to fix this vulnerability. Please read the Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms01-040.asp for information on obtaining this patch.

Acknowledgment:

  • Peter Grundl

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