From w.naef@iwar.org.uk Wed Sep 10 19:52:15 2003 From: "Wanja Eric Naef [IWS]" To: Infocon Date: Wed, 10 Sep 2003 23:34:45 +0100 Subject: [INFOCON] 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@cert.org 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. 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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----- ------------------------------------------------------------------------ Information is the currency of victory on the battlefield. GEN Gordon Sullivan, CSA (1993) ------------------------------------------------------------------------ INFOCON Mailing List @ IWS - The Information Warfare Site http://www.iwar.org.uk ------------------------------------------------------------------------ To subscribe, change your subscription or unsubscribe go to http://www.iwar.org.uk/mailman/listinfo/infocon/ ------------------------------------------------------------------------