[NEWS] Cisco 7920 Wireless IP Phone Privileges Escalation and Information Disclosure

From: SecuriTeam (support_at_securiteam.com)
Date: 11/21/05

  • Next message: SecuriTeam: "[EXPL] Macromedia Flash Plugin Buffer Overflow (Exploit, flash.ocx)" 
    To: list@securiteam.com
Date: 21 Nov 2005 16:22:06 +0200

    The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
    - - promotion

    The SecuriTeam alerts list - Free, Accurate, Independent.

    Get your security news from a reliable source.
    http://www.securiteam.com/mailinglist.html

    - - - - - - - - -

      Cisco 7920 Wireless IP Phone Privileges Escalation and Information
    Disclosure
    ------------------------------------------------------------------------

    SUMMARY

    "The
    <http://www.cisco.com/en/US/products/hw/phones/ps379/products_data_sheet09186a00801739bb.html> Cisco Wireless IP Phone 7920 is an easy-to-use IEEE 802.11b wireless IP phone that provides comprehensive voice communications in conjunction with Cisco CallManager and Cisco CallManager Express. "

    The first vulnerability in Cisco 7920 Wireless IP Phone is an SNMP service
    with fixed community strings that allow remote users to read, write, and
    erase the configuration of an affected device. The second vulnerability in
    Cisco 7920 Wireless IP Phone is an open VxWorks Remote Debugger on UDP
    port 17185 that may allow an unauthenticated remote user to access
    debugging information or cause a denial of service.

    DETAILS

    Vulnerable Systems:
     * Cisco 7920 Wireless IP Phone, firmware version 2.0 and prior

    Successful exploitation of these vulnerabilities may result in information
    leakage or denial of service attacks against an affected device. In the
    case of the Fixed SNMP Community Strings vulnerability, an attack may take
    the form of erasure or modification of the device configuration and
    personal user data.

    Privileges Escalation:
    The Cisco 7920 Wireless IP Phone provides an SNMP service with fixed
    read-only and read-write community strings of "public" and "private",
    respectively. These strings cannot be changed by the user and will allow
    remote users to issue an SNMP GetRequest or SetRequest to the phone. SNMP
    can be used to retrieve and modify the device configuration, including
    stored user data such as phone book entries. To address this
    vulnerability, Cisco has provided updated software that removes the SNMP
    functionality from this product.

    This issue is documented in Cisco bug ID
    <http://www.cisco.com/pcgi-bin/Support/Bugtool/onebug.pl?bugid=CSCsb75186>
    CSCsb75186 ( <http://tools.cisco.com/RPF/register/register.do> registered
    customers only) .

    Information Disclosure:
    The Cisco 7920 Wireless IP Phone listens on UDP port 17185 to allow
    connections from a VxWorks debugger. This port may allow remote users to
    collect debugging information or conduct a denial of service attack
    against an affected device. To address this vulnerability, Cisco has
    provided updated software that closes UDP port 17185.

    This issue is documented in Cisco bug ID
    <http://www.cisco.com/pcgi-bin/Support/Bugtool/onebug.pl?bugid=CSCsb38210>
    CSCsb38210 ( <http://tools.cisco.com/RPF/register/register.do> registered
    customers only) .

    Workaround:
     * For sites that restrict Cisco 7920 phones to one or more known subnets,
    Access Control Lists (ACLs) can be used to deny traffic to the affected
    ports.
            The following extended access-list can be adapted to your network.
    This example assumes that all Cisco 7920 phones are connected to the
    192.168.10.0 network and that all SNMP access is to be restricted to a
    management station with the IP address of 10.1.1.1:

    access-list 101 permit udp host 10.1.1.1 192.168.10.0 0.0.0.255 range 161
    162
    access-list 101 permit udp host 10.1.1.1 192.168.10.0 0.0.0.255 port 17185
    access-list 101 deny udp any 192.168.10.0 0.0.0.255 range 161 162
    access-list 101 deny udp any 192.168.10.0 0.0.0.255 port 17185
    access-list 101 permit ip any any

          The access-list must then be applied to all interfaces using
    configuration commands such as:

    interface ethernet 0/0
    ip access-group 101 in

     * Infrastructure ACLs (iACL)
          Although it is often difficult to block traffic transiting your
    network, it is possible to identify traffic which should never be allowed
    to target your infrastructure devices and block that traffic at the border
    of your network. Infrastructure ACLs are considered a network security
    best practice and should be considered as a long-term addition to good
    network security as well as a workaround for this specific vulnerability.
    The white paper entitled "Protecting Your Core: Infrastructure Protection
    Access Control Lists" presents guidelines and recommended deployment
    techniques for iACLs: <http://www.cisco.com/warp/public/707/iacl.html>
    http://www.cisco.com/warp/public/707/iacl.html

    ADDITIONAL INFORMATION

    The information has been provided by <mailto:psirt@cisco.com> Cisco
    Systems Product Security Incident Response Team.
    The original article can be found at:
    <http://www.cisco.com/warp/public/707/cisco-sa-20051116-7920.shtml>
    http://www.cisco.com/warp/public/707/cisco-sa-20051116-7920.shtml

    ========================================

    This bulletin is sent to members of the SecuriTeam mailing list.
    To unsubscribe from the list, send mail with an empty subject line and body to: list-unsubscribe@securiteam.com
    In order to subscribe to the mailing list, simply forward this email to: list-subscribe@securiteam.com

    ====================
    ====================

    DISCLAIMER:
    The information in this bulletin is provided "AS IS" without warranty of any kind.
    In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.

  • Next message: SecuriTeam: "[EXPL] Macromedia Flash Plugin Buffer Overflow (Exploit, flash.ocx)"

    Relevant Pages