26 july, 2010
-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1
Cisco Security Advisory: CDS Internet Streamer: Web Server Directory
Traversal Vulnerability
Advisory ID: cisco-sa-20100721-spcdn
http://www.cisco.com/warp/public/707/cisco-sa-20100721-spcdn.shtml
Revision 1.0
For Public Release 2010 July 21 1600 UTC (GMT)
+---------------------------------------------------------------------
Summary
=======
The Cisco Internet Streamer application, part of the Cisco Content
Delivery System, contains a directory traversal vulnerability on its web
server component that allows for arbitrary file access. By exploiting
this vulnerability, an attacker may be able to read arbitrary files on
the device, outside of the web server document directory, by using a
specially crafted URL.
An unauthenticated attacker may be able to exploit this issue to access
sensitive information, including the password files and system logs,
which could be leveraged to launch subsequent attacks.
Cisco has released free software updates that address this
vulnerability.
Workarounds that mitigate this vulnerability are available.
This advisory is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20100721-spcdn.shtml.
Affected Products
=================
All versions of system software on the Cisco Internet Streamer
application are vulnerable prior to the first fixed release.
Vulnerable Products
+------------------
To determine the software version 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
be provided. This example identifies a Cisco Content Delivery Engine
that is running Cisco Content Delivery System software release 2.5.3:
cdn-cde#show version
Content Delivery System Software (CDS)
Copyright ) 1999-2010 by Cisco Systems, Inc.
Content Delivery System Software Release 2.5.3 (build b8 Jan 21 2010)
Version: cde200-2.5.3.8
Compiled 16:07:11 Jan 21 2010 by ipvbuild
Compile Time Options: KQ SS
System was restarted on Thu Jun 3 04:09:25 2010.
The system has been up for 2 hours, 11 minutes, 27 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 the "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 Content
Delivery System, contains a directory traversal vulnerability on its web
server component that allows for arbitrary file access. It is possible
to read arbitrary files on the Cisco Content Delivery Engine running
the internet streamer application outside the web server's document
directory using a specially-crafted URL. This includes the password
files used to hold admin account details and system logs.
An unauthenticated attacker may be able to exploit this issue to access
sensitive information that could be leveraged to launch subsequent
attacks.
This vulnerability can be exploited over all open HTTP ports; TCP ports
80 (Default HTTP port), 443 (Default HTTPS port) and 8090 (Alternate
HTTP and HTTPS port), as well as those that are configured as part of
the HTTP proxy.
In Cisco content delivery system software 2.5.3 and earlier, it is
possible to configure "Enable Incoming Proxy", which when enabled,
accepts incoming requests on configured ports, in addition to TCP
port 80. The additional ports that the device will listen on for
HTTP requests is defined in the "List of Incoming HTTP Ports" field,
within "Devices > Devices > Application Control > Web > HTTP > HTTP
Connections" of the content delivery system manager menu. For further
information on HTTP settings, refer to the "Cisco Internet Streamer CDS
2.5 Software Configuration Guide - Configuring Devices" at the following
link:
http://www.cisco.com/en/US/docs/video/cds/cda/is/2_5/configuration_guide/configdevice.html.
This vulnerability is documented in the Cisco Bug ID CSCtd68063 and
has been assigned Common Vulnerabilities and Exposures (CVE) ID
CVE-2010-1577.
Vulnerability Scoring Details
+----------------------------
Cisco has provided scores 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
* CSCtd68063 ("CDS Internet Streamer: Web Server Directory Traversal
Vulnerability")
CVSS Base Score - 7.8
Access Vector - Network
Access Complexity - Low
Authentication - Single
Confidentiality Impact - Complete
Integrity Impact - None
Availability Impact - None
CVSS Temporal Score - 6.4
Exploitability - Functional
Remediation Level - Official-Fix
Report Confidence - Confirmed
Impact
======
An unauthenticated attacker may be able to exploit this issue to access
sensitive information, including the password files and system logs,
which could be leveraged to launch subsequent attacks.
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 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 | | |
| Delivery | First Fixed | Recommended |
| System | Release | Release |
| Software | | |
| Release | | |
|-----------+-------------+-------------|
| | Vulnerable, | |
| 2.2.x | Migrate to | |
| | 2.5.7 or | |
| | later | |
|-----------+-------------+-------------|
| | Vulnerable, | |
| 2.3.x | Migrate to | |
| | 2.5.7 or | |
| | later | |
|-----------+-------------+-------------|
| | Vulnerable, | |
| 2.4.x | Migrate to | |
| | 2.5.7 or | |
| | later | |
|-----------+-------------+-------------|
| 2.5.x | 2.5.7 | 2.5.9 |
+---------------------------------------+
Workarounds
===========
Service Rules
+------------
As an interim step prior to upgrading the Cisco content delivery system
software, it is possible to deny access to sensitive directories via
service rules. The following example shows denying access to move up a
directory level. This also caters for other directory moves, such as
"\.\./", ".\./" or "\../":
rule enable
rule action block pattern-list 1
rule pattern-list 1 url-regex ^http://.*/../.*
rule pattern-list 1 url-regex ^https://.*/../.*
For more information on configuring service rules and for instructions
on how to perform this via the content delivery system manager, consult
the Cisco Internet Streamer CDS 2.5 Software Configuration Guide at the
following link:
http://www.cisco.com/en/US/docs/video/cds/cda/is/2_5/configuration_guide/configdevice.html#wp1773573.
Obtaining Fixed Software
========================
Cisco has released free software updates that address this
vulnerability. 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 psirt@cisco.com or security-alert@cisco.com 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)
* e-mail: tac@cisco.com
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 reported to Cisco by BT and identified by
Christopher Richardson & Simon John.
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-20100721-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.
* cust-security-announce@cisco.com
* first-bulletins@lists.first.org
* bugtraq@securityfocus.com
* vulnwatch@vulnwatch.org
* cisco@spot.colorado.edu
* cisco-nsp@puck.nether.net
* full-disclosure@lists.grok.org.uk
* comp.dcom.sys.cisco@newsgate.cisco.com
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 | 2010 July 21 | 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.
+--------------------------------------------------------------------
Copyright 2008-2010 Cisco Systems, Inc. All rights reserved.
+--------------------------------------------------------------------
Updated: Jul 21, 2010 Document ID: 112019
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)
iEYEARECAAYFAkxHEIEACgkQ86n/Gc8U/uBiSQCeO8DOXUa1HP5mwVgPYQVkEVZJ
fBAAnjNOGCtXhg/W5ktGiM+LNZ+Y5/Sg
=Hf9O
-----END PGP SIGNATURE-----