Fw: Microsoft Security Bulletin MS02-027
- From: "Jim Harrison" <jim@xxxxxxxxxxxx>
- To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
- Date: Tue, 11 Jun 2002 17:18:20 -0700
Pay close attention to this one, folks!
Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://isaserver.org/authors/harrison/
Read the books!
----- Original Message -----
From: "Jerry Bryant [MS]" <jbryant@xxxxxxxxxxxxxxxxxxxx>
Newsgroups:
microsoft.public.security,microsoft.public.isa,microsoft.public.isaserver,mi
crosoft.public.windows.inetexplorer.ie55.browser,microsoft.public.windows.in
etexplorer.ie6.browser
Sent: Tuesday, June 11, 2002 4:40 PM
Subject: Microsoft Security Bulletin MS02-027
Title: Unchecked Buffer in Gopher Protocol Handler Can Run Code
of Attacker's Choice (Q323889)
Date: 11 June 2002
Software: Internet Explorer, Proxy Server, Internet Security and
Acceleration Server
Impact: Run Code of Attacker's Choice
Max Risk: Critical
Bulletin: MS02-027
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS02-027.asp.
- ----------------------------------------------------------------------
Issue:
======
This is a work-around bulletin that details steps customers can take to
protect themselves against a publicly disclosed vulnerability until patches
are available.
The Gopher protocol is a legacy protocol that provides for the transfer of
text-based information across the Internet. Information on Gopher servers is
hierarchically presented using a menu system, and multiple Gopher servers
can be linked together to form a collective "Gopherspace".
There is an unchecked buffer in a piece of code which handles the response
from Gopher servers. This code is used independently in IE, ISA, and Proxy
Server. A security vulnerability results because it is possible for an
attacker to attempt to exploit this flaw by mounting a buffer overrun attack
through a specially crafted server response. The attacker could seek to
exploit the vulnerability by crafting a web page that contacted a server
under the attacker's control. The attacker could then either post this page
on a web site or send it as an HTML email. When the page was displayed and
the server's response received and processed, the attack would be carried
out.
A successful attack requires that the attacker be able to send information
to the intended target using the Gopher protocol. Anything which inhibited
Gopher connectivity could protect against attempts to exploit this
vulnerability. In the case of IE, the code would be run in the user's
context. As a result, any limitations on the user would apply to the
attacker's code as well.
Mitigating Factors:
====================
- A successful attack requires that the attacker's server be
able to deliver information to the target using the Gopher
protocol. Customers who block Gopher at the perimeter would be
protected against attempts to exploit this vulnerability across
the Internet.
- In the case of IE, code would run in the security context of
the user. As a result, any limitations on the user's ability
would also restrict the actions an attacker's code could take.
- A successful attack against ISA and Proxy servers would
require that the malicious response be received by the web
proxy service. In practical terms, this means that a proxy
client would have to submit the initial request through the
proxy server.
Risk Rating:
============
- Internet systems: Critical
- Intranet systems: Critical
- Client systems: Critical
Patch Availability:
===================
- A patch is currently under development to fix this
vulnerability. Please read the Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms02-027.asp
for workaround information while patches are developed.
- ---------------------------------------------------------------------
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--
Regards,
Jerry Bryant - MCSE, MCDBA
Microsoft IT Communities
Get Secure! www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
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