Title: Malformed RPC Request Can Cause Service Failure
Date: 26 July 2001
Software: Exchange Server 5.5, Exchange Server 2000,
SQL Server 7.0, SQL Server 2000, Windows NT 4.0,
Windows 2000
Impact: Denial of service
Bulletin: MS01-041

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-041.asp.

Issue:

Several of the RPC servers associated with system services in
Microsoft
Exchange, SQL Server, Windows NT 4.0 and Windows 2000 do not
adequately
validate inputs, and in some cases will accept invalid inputs that
prevent normal processing. The specific input values at issue here
vary
from RPC server to RPC server.

An attacker who sent such inputs to an affected RPC server could
disrupt its service. The precise type of disruption would depend on
the
specific service, but could range in effect from minor (e.g., the
service temporarily hanging) to major (e.g., the service failing in a
way that would require the entire system to be restarted).

Mitigating Factors:

• Proper firewalling would help minimize an affected system's
  exposure to attack by Internet-based users. In general, a
  firewall should block access to all RPC services except
  those that are specifically intended for use by untrusted users.

Patch Availability:

• A patch is available to fix this vulnerability. Please read the
  Security Bulletin
  http://www.microsoft.com/technet/security/bulletin/ms01-041.asp
  for information on obtaining this patch.

Acknowledgment:

• Bindview's Razor Team (http://razor.bindview.com)

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