March 2007
Cisco Security Advisory: Cisco Unified IP Conference Station and IP Phone Vulnerabilities
ID: 76
Ref: 018/2007
Date: 07 March 2007:18:44:05
Version: 1
Title: Cisco Security Advisory: Cisco Unified IP Conference Station and IP Phone Vulnerabilities
Abstract: Certain Cisco Unified IP Conference Station and IP Phone devices contain vulnerabilities which may allow unauthorized users to gain administrative access to vulnerable devices.
Vendors affected: Cisco
Applications affected: Cisco
Cisco Security Advisory: Cisco Unified IP Conference Station and IP Phone Vulnerabilities
Detail
======
Advisory ID: cisco-sa-20070221-phone
http://www.cisco.com/warp/public/707/cisco-sa-20070221-phone.shtml
Revision 1.0
For Public Release 2007 February 21 1600 UTC (GMT)
-----------------------------------------------------------------------
Summary
=======
Certain Cisco Unified IP Conference Station and IP Phone devices contain vulnerabilities which may allow unauthorized users to gain administrative access to vulnerable devices.
Cisco Unified IP Conference Station Administrative Bypass Vulnerability
Cisco Unified IP Conference Station 7935 and 7936 devices do not require a password when a URL is accessed directly via the administrator HTTP interface. There is a workaround for this vulnerability.
Cisco Unified IP Phone Default Account and Privilege Escalation Vulnerabilities
Cisco Unified IP Phone 7906G, 7911G, 7941G, 7961G, 7970G and 7971G devices contain a hard coded default user account with a default password which is remotely accessible via a Secure Shell (SSH) server enabled on the phone. This default user account may be leveraged to gain administrative access to a vulnerable phone via a privilege escalation vulnerability.
The default user account may also execute commands causing a phone to become unstable and result in a denial of service. The default user account can not be disabled, removed or have its password changed. There are mitigations available for these vulnerabilities.
Cisco has made free software available to address these issues for affected customers.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20070221-phone.shtml
Affected Products
=================
This section provides details on affected products.
Vulnerable Products
+------------------
This section provides details on vulnerable products.
Cisco Unified IP Conference Station
+----------------------------------
+---------------------------------------+
| Model | Affected Firmware Version |
|--------+------------------------------|
| 7935 | 3.2(15) and earlier |
|--------+------------------------------|
| 7936 | 3.3(12) and earlier |
+---------------------------------------+
Cisco Unified IP Phone
+---------------------
+---------------------------------------+
| Model | Firmware Version |
|---------+-----------------------------|
| 7906G | 8.0(4)SR1 and earlier |
|---------+-----------------------------|
| 7911G | 8.0(4)SR1 and earlier |
|---------+-----------------------------|
| 7941G | 8.0(4)SR1 and earlier |
|---------+-----------------------------|
| 7961G | 8.0(4)SR1 and earlier |
|---------+-----------------------------|
| 7970G | 8.0(4)SR1 and earlier |
|---------+-----------------------------|
| 7971G | 8.0(4)SR1 and earlier |
+---------------------------------------+
The version of firmware running on an IP phone can be determined via the Settings menu on a phone.
In most deployments, Cisco Unified CallManager (CUCM) can also be used to accurately determine the version of firmware that is supposed to be running on an IP phone. While CUCM maintains a record of the firmware it last deployed to an IP phone, it is possible for a user to change the firmware version on an IP phone.
Products Confirmed Not Vulnerable
+--------------------------------
Cisco Unified IP Phone 7902G, 7905, 7905G, 7910, 7912, 7912G, 7920, 7921G, 7940, 7960 and 7985 devices are not vulnerable to the default account and privilege escalation vulnerability.
No other Cisco products are known to be vulnerable.
Details
=======
Cisco Unified IP Conference Station Administrative Bypass Vulnerability
+--------------------------------------------------------
Cisco Unified IP Conference Station 7935 and 7936 devices provide integrated speaker phone services for a networked environment. 7935/
7936 devices can be managed via an administrative HTTP interface and/ or a with Cisco Unified CallManager (CUCM) system. The administrative HTTP interface is protected by a user configurable password. If a user knows the direct path to a management URL, it may be possible to access the administrative HTTP interface without being prompted for authentication. The vulnerability occurs because vulnerable IP Conference Station devices incorrectly maintain the state of administrator login sessions. If an administrator logs into a vulnerable device via the HTTP interface, the administrator's credentials will be cached even after the administrator logs out of the device. This leaves a window of opportunity for an unauthorized user to gain complete administrative access to a vulnerable device. If an administrator never accesses a potentially vulnerable device via the HTTP interface, the device is not vulnerable to the authentication bypass attack. It is possible to reset to an IP Conference Station to a non-vulnerable state by power-cycling the device or performing a reboot operation (not a reload operation) via the CUCM system which manages the device. This defect is documented in Cisco Bug ID CSCsg26788 ( registered customers only) .
Cisco Unified IP Phone Default Account and Privilege Escalation Vulnerabilities
+--------------------------------------------------------------
Cisco Unified IP Phone 7906G, 7911G, 7941G, 7961G, 7970G and 7971G devices provide integrated phone service for a networked environment.
These IP phones devices contain a hard coded default user account with a default password that is used for debugging purposes and is embedded into the phone's firmware. This default user account cannot be disabled, removed or have its password changed. Due to an implementation error, it possible to use the hard coded default user account to remotely access the Command Line Interface (CLI) of a vulnerable IP phone via a phone's SSH server. The SSH server is only supposed to authenticate user accounts which have been created by an administrator. The SSH server may not be disabled. The firmware update including the solution for this vulnerability prohibits the default user account from accessing a phone via the SSH server, but the default user account may still access the phone via the console serial port. This defect is documented in Cisco Bug ID CSCsg34758 ( registered customers only).
Using the default user account to access the CLI of a vulnerable IP phone device (via SSH or the console serial port), an attacker can execute a number of commands which may result in the escalation of privileges leading to complete compromise of an affected IP phone or cause an IP phone to become unstable and crash. These defects are documented in Cisco Bug IDs
CSCsg34789 ( registered customers only) and CSCsg42627 ( registered customers only).
Vulnerability Scoring Details
=============================
Cisco is providing scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS).
Cisco will provide a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.
Cisco PSIRT will set the bias in all cases to normal. Customers are encouraged to apply the bias parameter when determining the environmental impact of a particular vulnerability.
CVSS is a standards based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.
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
CSCsg26788 - IP Conference Station HTTP Interface Administrator Bypass
+---------------------------------------------------------------------
CVSS Base Score: 10
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: Complete
Integrity Impact: Complete
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 8.3
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsg34758 - IP Phone SSH Vulnerability
+--------------------------------------
CVSS Base Score: 10
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: Complete
Integrity Impact: Complete
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 8.3
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsg34789 - Filesystem Privilege Escalation
+-------------------------------------------
CVSS Base Score: 6
Access Vector: Remote
Access Complexity: Low
Authentication: Required
Confidentiality Impact: Complete
Integrity Impact: Complete
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 5
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsg42627 - Filesystem Denial of Service
+----------------------------------------
CVSS Base Score: 2
Access Vector: Remote
Access Complexity: Low
Authentication: Required
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 1.7
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
Impact
======
Successful exploitation of the Conference Station administrative bypass or IP
Phone default account and privilege escalation vulnerabilities may result in
the complete compromise of a vulnerable device.
Software Version 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.
Cisco Unified IP Conference Station
+----------------------------------
+---------------------------------------+
| Model | Fixed Firmware Version |
|--------+------------------------------|
| 7935 | 3.2(16) |
|--------+------------------------------|
| 7936 | 3.3(13) |
+---------------------------------------+
Cisco Unified IP Phone
+---------------------
+---------------------------------------+
| Model | Fixed Firmware Version |
|--------+------------------------------|
| 7906G | 8.0(4)SR2, 8.2(1) |
|--------+------------------------------|
| 7911G | 8.0(4)SR2, 8.2(1) |
|--------+------------------------------|
| 7941G | 8.0(4)SR2, 8.2(1) |
|--------+------------------------------|
| 7961G | 8.0(4)SR2, 8.2(1) |
|--------+------------------------------|
| 7970G | 8.0(4)SR2, 8.2(1) |
|--------+------------------------------|
| 7971G | 8.0(4)SR2, 8.2(1) |
+---------------------------------------+
Fixed software can be obtained here:
http://www.cisco.com/cgi-bin/tablebuild.pl/ip-7900ser
Workarounds
===========
For Cisco Unified Conference Station and IP Phone devices, the following
mitigations have been provided.
The effectiveness of any mitigation 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 mitigation or fix is the most appropriate for use in
the intended network before it is deployed.
Additional mitigations that can be deployed on Cisco devices within the network
are available in the Cisco Applied Intelligence companion document for this advisory:
http://www.cisco.com/warp/public/707/cisco-air-20070221-phone.shtml
Apply access control lists (ACLs) on routers, switches and firewalls that
filter traffic to vulnerable Conference Station and IP Phone devices so
that traffic is only allowed from stations that need to remotely administer
the devices.
It is possible to workaround the Cisco Unified IP Conference Station
Administrative Bypass vulnerability by ensuring that the administrative
HTTP interface is not used to manage any vulnerable devices. If the HTTP
interface must be used, vulnerable devices should be power cycled or rebooted
via a CUCM system after system changes are made.
Obtaining Fixed Software
========================
Cisco will make free software available to address this vulnerability
for affected customers. This advisory will be updated as fixed software
becomes available. 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/public/sw-license-agreement.html,
or as otherwise set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center /sw-usingswc.shtml.
Do not contact either "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 agreement 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 who do not hold a Cisco service
contract and customers who purchase through third-party vendors but are
unsuccessful at obtaining fixed software through their point of sale should
get their 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
Have your product serial number available and give the URL of this notice as
evidence of your entitlement to a free upgrade. Free upgrades for non-contract
customers must be requested through the TAC.
Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
for additional TAC contact information, including special 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.
The Conference Station administrative bypass vulnerability was reported to
Cisco by Christian Reichert, Christian Blum and Jens Link of Intact Integrated
Services.
The IP Phone default account and privilege escalation vulnerabilities were
discovered internally by Cisco.
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-20070221-phone.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-teams@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 | | Initial |
| 1.0 | 2007-February-21 | 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.
______________________________________________________________________________
CPNI values your feedback.
1. Which of the following most reflects the value of the advisory to you?
(Place an 'X' next to your choice)
Very useful:__ Useful:__ Not useful:__
2. If you did not find it useful, why not?
3. Any other comments? How could we improve our advisories?
Thank you for your contribution.
______________________________________________________________________________
CPNI wishes to acknowledge the contributions of Cisco for the information
contained in this advisory.
______________________________________________________________________________