[SECURITY-L] [cais em cais.rnp.br: CAIS-Alerta: Vulnerabilidade no Microsoft Winsock Proxy e ISA Firewall (331066)]

Qui Abr 10 14:46:52 -03 2003

----- Forwarded message from Centro de Atendimento a Incidentes de Seguranca <cais em cais.rnp.br> -----

From: Centro de Atendimento a Incidentes de Seguranca <cais em cais.rnp.br>
Subject: CAIS-Alerta: Vulnerabilidade no Microsoft Winsock Proxy e ISA Firewall
 (331066)
To: rnp-alerta em cais.rnp.br, rnp-seg em cais.rnp.br
Date: Thu, 10 Apr 2003 14:27:01 -0300 (BRT)

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Prezados,

O CAIS está repassando o alerta divulgado pela Microsoft, Microsoft
Security Bulletin MS03-012: Flaw In Winsock Proxy Service And ISA Firewall
Service Can Cause Denial Of Service (331066), que trata de uma
vulnerabilidade identificada no Winsock Proxy Service e ISA Firewall
Service que pode permitir a um atacante realizar um ataque de negacao de
servico (DoS).

Sistemas Afetados:

	. Microsoft Proxy Server 2.0
	. Microsoft ISA Server

Correções disponíveis:

A correção consiste na aplicação do patch recomendado pela Microsoft e
disponíveis nas URLs listadas abaixo.

	. Proxy Server 2.0:
http://microsoft.com/downloads/details.aspx?FamilyId=C81688B7-20FB-45EB-BAFD-031A0D2923E6&displaylang=en

	. ISA Server:

	English:
http://microsoft.com/downloads/details.aspx?FamilyId=3C43FAD2-A888-4603-84B7-1053C8663436&displaylang=en

	French:
http://microsoft.com/downloads/details.aspx?FamilyId=3C43FAD2-A888-4603-84B7-1053C8663436&displaylang=fr

	German:
http://microsoft.com/downloads/details.aspx?FamilyId=3C43FAD2-A888-4603-84B7-1053C8663436&displaylang=de

	Spanish:
http://microsoft.com/downloads/details.aspx?FamilyId=3C43FAD2-A888-4603-84B7-1053C8663436&displaylang=es

	Japanese:
http://microsoft.com/downloads/details.aspx?FamilyId=3C43FAD2-A888-4603-84B7-1053C8663436&displaylang=ja

Maiores informações:

http://www.microsoft.com/technet/security/bulletin/ms03-012.asp

Identificador do CVE: CAN-2003-0110 (http://cve.mitre.org)

O CAIS recomenda aos administradores de plataformas Microsoft que
mantenham seus sistemas e aplicativos sempre atualizados.

Atenciosamente,

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Title:      Flaw In Winsock Proxy Service And ISA Firewall Service
	    Can Cause Denial Of Service (331066)
Date:       09 April 2003
Software:   Microsoft Proxy Server 2.0, Microsoft ISA Server
Impact:     denial of service
Max Risk:   Important
Bulletin:   MS03-012

Microsoft encourages customers to review the Security Bulletins
at:

http://www.microsoft.com/technet/security/bulletin/MS03-012.asp
http://www.microsoft.com/security/security_bulletins/ms03-012.asp
- -------------------------------------------------------------------

Issue:
======
There is a flaw in the Winsock Proxy service in Microsoft Proxy
Server 2.0, and the Microsoft Firewall service in ISA Server 2000,
that would allow an attacker on the internal network to send a
specially crafted packet that would cause the server to stop
responding to internal and external requests. Receipt of such a
packet would cause CPU utilization on the server to reach 100%, and
thus make the server unresponsive. The Winsock Proxy service and
Microsoft Firewall service work with FTP, telnet, mail, news,
Internet Relay Chat (IRC), or other client applications that are
compatible with Windows Sockets (Winsock). These services allow
these applications to perform as if they were directly connected to
the Internet. These services redirect the necessary communications
functions to a Proxy Server 2.0 or ISA Server computer, thus
establishing a communication path from the internal application to
the Internet through it.

Mitigating Factors:
====================

- - The vulnerability would not enable an attacker to gain any
privileges on an affected Proxy Server 2.0 or ISA Server computer
or compromise any cached content. It is strictly a denial of
service.

- - ISA Server computers running in cache mode are not affected
because the Microsoft Firewall service is disabled by default.

Risk Rating:
============
Important

Patch Availability:
===================
A patch is available to fix this vulnerability. Please read the
Security Bulletins at

http://www.microsoft.com/technet/security/bulletin/ms03-012.asp
http://www.microsoft.com/security/security_bulletins/ms03-12.asp

for information on obtaining this patch.

- ----------------------------------------------------------------

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT
DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING
THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS
SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT,
INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR
SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS
HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME
STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR
CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION
MAY NOT APPLY.

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