CERT Advisory CA-2003-23 RPCSS Vulnerabilities in Microsoft Windows
-----BEGIN PGP SIGNED MESSAGE-----
CERT Advisory CA-2003-23 RPCSS Vulnerabilities in Microsoft Windows
Original release date: September 10, 2003
Last revised: --
Source: CERT/CC
A complete revision history can be found at the end of this file.
Systems Affected
* Microsoft Windows NT Workstation 4.0
* Microsoft Windows NT Server 4.0
* Microsoft Windows NT Server 4.0, Terminal Server Edition
* Microsoft Windows 2000
* Microsoft Windows XP
* Microsoft Windows Server 2003
Overview
Microsoft has published a bulletin describing three vulnerabilities
that affect numerous versions of Microsoft Windows. Two of these
vulnerabilities are remotely exploitable buffer overflows that may
allow an attacker to execute arbitrary code with system privileges.
The third vulnerability may allow a remote attacker to cause a denial
of service.
I. Description
The Microsoft RPCSS Service is responsible for managing Remote
Procedure Call (RPC) messages. There are two buffer overflow
vulnerabilities in the RPCSS service, which is enabled by default on
many versions of Microsoft Windows. These buffer overflows occur in
sections of code that handle DCOM activation messages sent to the
RPCSS service.
The CERT/CC is tracking these vulnerabilities as VU#483492 and
VU#254236, which correspond to CVE candidates CAN-2003-0715 and
CAN-2003-0528, respectively. The buffer overflows discussed in this
advisory are different than those discussed in previous advisories.
Microsoft has also published information regarding a denial-of-service
vulnerability in the RPCSS service. This vulnerability only affects
Microsoft Windows 2000 systems.
The CERT/CC is tracking this vulnerability as VU#326746, which
corresponds to CVE candidate CAN-2003-0605. This vulnerability was
previously discussed in CA-2003-19.
II. Impact
By exploiting either of the buffer overflow vulnerabilities, remote
attackers may be able to execute arbitrary code with Local System
privileges.
By exploiting the denial-of-service vulnerability, remote attackers
may be able to disrupt the RPCSS service. This may result in general
system instability and require a reboot.
III. Solution
Apply a patch from Microsoft
Microsoft has published Microsoft Security Bulletin MS03-039 to
address this vulnerability. For more information, please see
http://www.microsoft.com/technet/security/bulletin/MS03-039.asp
This bulletin supersedes MS03-026.
Block traffic to and from common Microsoft RPC ports
As an interim measure, users can reduce the chance of successful
exploitation by blocking traffic to and from well-known Microsoft RPC
ports, including
* Port 135 (tcp/udp)
* Port 137 (udp)
* Port 138 (udp)
* Port 139 (tcp)
* Port 445 (tcp/udp)
* Port 593 (tcp)
To prevent compromised hosts from contacting other vulnerable hosts,
the CERT/CC recommends that system administrators filter the ports
listed above for both incoming and outgoing traffic.
Disable COM Internet Services and RPC over HTTP
COM Internet Services (CIS) is an optional component that allows RPC
messages to be tunneled over HTTP ports 80 and 443. As an interim
measure, sites that use CIS may wish to disable it as an alternative
to blocking traffic to and from ports 80 and 443.
Disable DCOM
Disable DCOM as described in MS03-039 and Microsoft Knowledge Base
Article 825750.
_________________________________________________________________
This document was written by Jeffrey P. Lanza and is based upon the
information in MS03-039.
______________________________________________________________________
This document is available from:
http://www.cert.org/advisories/CA-2003-23.html
______________________________________________________________________
CERT/CC Contact Information
Email: cert@xxxxxxxx
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
Postal address:
CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890
U.S.A.
CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) /
EDT(GMT-4) Monday through Friday; they are on call for emergencies
during other hours, on U.S. holidays, and on weekends.
Using encryption
We strongly urge you to encrypt sensitive information sent by email.
Our public PGP key is available from
http://www.cert.org/CERT_PGP.key
If you prefer to use DES, please call the CERT hotline for more
information.
Getting security information
CERT publications and other security information are available from
our web site
http://www.cert.org/
To subscribe to the CERT mailing list for advisories and bulletins,
send email to majordomo@xxxxxxxxx Please include in the body of your
message
subscribe cert-advisory
* "CERT" and "CERT Coordination Center" are registered in the U.S.
Patent and Trademark Office.
______________________________________________________________________
NO WARRANTY
Any material furnished by Carnegie Mellon University and the Software
Engineering Institute is furnished on an "as is" basis. Carnegie
Mellon University makes no warranties of any kind, either expressed or
implied as to any matter including, but not limited to, warranty of
fitness for a particular purpose or merchantability, exclusivity or
results obtained from use of the material. Carnegie Mellon University
does not make any warranty of any kind with respect to freedom from
patent, trademark, or copyright infringement.
______________________________________________________________________
Conditions for use, disclaimers, and sponsorship information
Copyright 2003 Carnegie Mellon University.
Revision History
Sep 10, 2003: Initial release
-----BEGIN PGP SIGNATURE-----
Version: PGP 6.5.8
iQCVAwUBP1+NqTpmH2w9K/0VAQHUbwP/aQ8osvAzy2BswiPOpLFoUhC4GIjdtXcx
mGcVDXyVcu4v4pKym8+ojIrQhdWKwOt9ZL8+RSaq8IMjUgE11BX5zA1/1WZhkE7p
hlu+HDTkDc5WvFrNqbChrC3gX2fgjI9hjx361SXuhgXAxI5nLz2of50pb+GxPWvA
ZQJp4ymyuyI=
=A+8F
-----END PGP SIGNATURE-----