Uočena je jedna sigurnosna ranjivost vezana uz Cisco Content Delivery System (Cisco CDS) koju je moguće iskoristiti za DoS (eng. Denial of Service) napad.

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Cisco Security Advisory: Cisco Content Delivery System Internet
Streamer: Web Server Vulnerability

Advisory ID: cisco-sa-20110525-spcdn

Revision 1.0

For Public Release 2011 May 25 1600 UTC (GMT)

+---------------------------------------------------------------------

Summary
=======

The Cisco Internet Streamer application, part of the Cisco Content
Delivery System (Cisco CDS), contains a vulnerability in its web
server component that could cause the web server engine to crash when
processing specially crafted URLs.

Cisco has released free software updates that address this
vulnerability.

Workarounds that mitigate this vulnerability are not available.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20110525-spcdn.shtml

Affected Products
=================

System software versions 2.5.7 and later on the Cisco Internet
Streamer application are vulnerable prior to the first fixed release.
System software versions prior to 2.5.7 are not affected by this
vulnerability.

Vulnerable Products
+------------------

To determine the software version that is running on a Cisco Content
Delivery Engine, log in to the device and issue the show version
command-line interface (CLI) command to display the system banner.
Cisco CDS Internet Streamer software will identify itself as "Content
Delivery System Software Release". On the same line of output, the
version number will also be provided. This example identifies a Cisco
Content Delivery Engine that is running Cisco Content Delivery System
software release 2.5.9 build 5:

    cdn-cde#show version
    Content Delivery System Software (CDS)
    Copyright (c) 1999-2010 by Cisco Systems, Inc.
    Content Delivery System Software Release 2.5.9 (build b5 Jun 16 2010)
    Version: cde200-2.5.9.5

    Compiled 22:10:04 Jun 16 2010 by ipvbuild
    Compile Time Options: KQ SS

    System was restarted on Wed Sep 15 06:50:22 2010.
    The system has been up for 1 hour, 25 minutes, 6 seconds.

    cdn-cde#

Alternatively, the Content Delivery System Manager home page gives a
brief summary of the software versions in use on all the devices in
the content delivery system network.

To view the software version running on a particular device, choose
Devices > Devices. The Devices Table page displays the software
version for each device listed. For further information on finding
the software version, refer to "Maintaining the Internet Streamer
CDS" at the following link:

http://www.cisco.com/en/US/docs/video/cds/cda/is/2_5/configuration_guide/maint.html#wp1198510

Products Confirmed Not Vulnerable
+--------------------------------

Cisco Content Delivery Engines running TV streaming content delivery
applications and the Video Navigator application are not affected.

No other Cisco products are currently known to be affected by this
vulnerability.

Details
=======

The Cisco Internet Streamer application provides edge caching,
content streaming, and downloads to subscriber IP devices such as
PCs.

The Cisco Internet Streamer application, part of the Cisco CDS,
contains a vulnerability on its web server component that could cause
the web server engine to crash when processing specially crafted
URLs.

An unauthenticated attacker may be able to exploit this vulnerability
to cause a denial of service condition on the web server that is
running on the Service Engine. The device will remain operational,
and the Web Engine will restart if the attack stops.

This vulnerability is documented in the Cisco Bug IDs CSCtg67333 and
CSCth25341 and has been assigned Common Vulnerabilities and Exposures
(CVE) ID CVE-2011-1649. Both bugs fixes are required for a full
solution.

Vulnerability Scoring Details
=============================

Cisco has provided a score for the vulnerability in this advisory
based on the Common Vulnerability Scoring System (CVSS). The CVSS
scoring in this Security Advisory is done in accordance with CVSS
version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability
severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of
the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding
CVSS at:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to help compute the
environmental impact for individual networks at:

http://intellishield.cisco.com/security/alertmanager/cvss


* CSCtg67333/CSCth25341 ("Crafted URL may crash webengine in CDS
Internet Streamer")

CVSS Base Score - 7.8
    Access Vector -            Network
    Access Complexity -        Low
    Authentication -           None
    Confidentiality Impact -   None
    Integrity Impact -         None
    Availability Impact -      Complete

CVSS Temporal Score - 6.4
    Exploitability -           Functional
    Remediation Level -        Official-Fix
    Report Confidence -        Confirmed


Impact
======

Successful exploitation of the vulnerability may cause the Web Engine
of the Cisco Internet Streamer application to crash.

The device will remain operational, and the Web Engine will restart
if the attack stops.

A sustained attack will prevent the distribution of HTML content to
end users.

Software Versions and Fixes
===========================

When considering software upgrades, also consult
http://www.cisco.com/go/psirt and any subsequent advisories to determine
exposure and a complete upgrade solution.

In all cases, customers should exercise caution to be certain the
devices to be upgraded contain sufficient memory and that current
hardware and software configurations will continue to be supported
properly by the new release. If the information is not clear, contact
the Cisco Technical Assistance Center (TAC) or your contracted
maintenance provider for assistance.

The recommended release contains other software fixes that are
recommended by Cisco. For further information please consult the
Release Notes for Cisco Internet Streamer CDS 2.5.9 at the following
link:

http://www.cisco.com/en/US/docs/video/cds/cda/is/2_5/release_notes/CDS_RelNotes2_5_9.html#wp100128

+------------------------------------------------------------+
|  Cisco Content   |                           | Recommended |
| Delivery System  |    First Fixed Release    |   Release   |
| Software Release |                           |             |
|------------------+---------------------------+-------------|
| 2.2.x            | Not Vulnerable            |             |
|------------------+---------------------------+-------------|
| 2.3.x            | Not Vulnerable            |             |
|------------------+---------------------------+-------------|
| 2.4.x            | Not Vulnerable            |             |
|------------------+---------------------------+-------------|
|                  | Releases prior to 2.5.7   | 2.5.9 build |
| 2.5.x            | are not affected, first   | 126         |
|                  | fixed in 2.5.9 build 126  |             |
+------------------------------------------------------------+

Workarounds
===========

There are no workarounds for the vulnerability documented in this
security advisory.

Obtaining Fixed Software
========================

Cisco has released free software updates that address these
vulnerabilities. Prior to deploying software, customers should
consult their maintenance provider or check the software for feature
set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature
sets they have purchased. By installing, downloading, accessing
or otherwise using such software upgrades, customers agree to be
bound by the terms of Cisco's software license terms found at
http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html,
or as otherwise set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact Ova e-mail adresa je zaštićena od spambota. Potrebno je omogućiti JavaScript da je vidite. or Ova e-mail adresa je zaštićena od spambota. Potrebno je omogućiti JavaScript da je vidite. for
software upgrades.

Customers with Service Contracts
+-------------------------------

Customers with contracts should obtain upgraded software through
their regular update channels. For most customers, this means that
upgrades should be obtained through the Software Center on Cisco's
worldwide website at http://www.cisco.com.

Customers using Third Party Support Organizations
+------------------------------------------------

Customers whose Cisco products are provided or maintained through
prior or existing agreements with third-party support organizations,
such as Cisco Partners, authorized resellers, or service providers
should contact that support organization for guidance and assistance
with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific
customer situations, such as product mix, network topology, traffic
behavior, and organizational mission. Due to the variety of affected
products and releases, customers should consult with their service
provider or support organization to ensure any applied workaround or
fix is the most appropriate for use in the intended network before it
is deployed.

Customers without Service Contracts
+----------------------------------

Customers who purchase direct from Cisco but do not hold a Cisco
service contract, and customers who purchase through third-party
vendors but are unsuccessful in obtaining fixed software through
their point of sale should acquire upgrades by contacting the Cisco
Technical Assistance Center (TAC). TAC contacts are as follows.

  * +1 800 553 2447 (toll free from within North America)
  * +1 408 526 7209 (toll call from anywhere in the world)
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Customers should have their product serial number available and be
prepared to give the URL of this notice as evidence of entitlement to
a free upgrade. Free upgrades for non-contract customers must be
requested through the TAC.

Refer to
http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html
for additional TAC contact information, including localized telephone
numbers, and instructions and e-mail addresses for use in various
languages.

Exploitation and Public Announcements
=====================================

The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.

This vulnerability was discovered when handling customer support
calls.

Status of this Notice: FINAL
============================

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY
KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE
INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS
AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS
DOCUMENT AT ANY TIME.

A stand-alone copy or Paraphrase of the text of this document that
omits the distribution URL in the following section is an
uncontrolled copy, and may lack important information or contain
factual errors.

Distribution
============

This advisory is posted on Cisco's worldwide website at:

http://www.cisco.com/warp/public/707/cisco-sa-20110525-spcdn.shtml

In addition to worldwide web posting, a text version of this notice
is clear-signed with the Cisco PSIRT PGP key and is posted to the
following e-mail and Usenet news recipients.

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Future updates of this advisory, if any, will be placed on Cisco's
worldwide website, but may or may not be actively announced on
mailing lists or newsgroups. Users concerned about this problem are
encouraged to check the above URL for any updates.

Revision History
================

+------------------------------------------------------------+
| Revision 1.0   | 2011-May-25  | Initial public release.    |
+------------------------------------------------------------+

Cisco Security Procedures
=========================

Complete information on reporting security vulnerabilities in Cisco
products, obtaining assistance with security incidents, and
registering to receive security information from Cisco, is available
on Cisco's worldwide website at
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html.
This includes instructions for press inquiries regarding Cisco
security notices. All Cisco security advisories are available at
http://www.cisco.com/go/psirt.

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Copyright 2010-2011 Cisco Systems, Inc. All rights reserved.
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Updated: May 25, 2011                             Document ID: 112138

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