Cleartext Storage of Phone Password in Cisco IP Phones

Title

Cleartext Storage of Phone Password

Product

Cisco IP Phone Series 78x1, 88x5, 88x1, 7832, 8832, 8821 and 3905

Vulnerable Version

Firmware <14.1.1, Firmware <11.0(6)SR2 (device model 8821), Firmware <9.4(1)SR5 (device model 3905)

Fixed Version

Firmware 14.1.1, 11.0(6)SR2, 9.4(1)SR5

CVE Number

CVE-2022-20660

Impact

medium

Homepage

https://www.cisco.com

Found

15.04.2021

By

Gerhard Hechenberger (Office Vienna) and Steffen Robertz (Office Vienna)

Multiple Cisco IP phones store the configured phone password in cleartext in their unencrypted flash memory. Therefore, the password can be extracted without difficulty if physical access to a phone is possible. If this password is used on multiple phones, an attacker gains access to the administrative settings of all these devices.

 

Vendor description

"The Cisco® IP Phone 7800 Series is a cost-effective, high-fidelity voice communications portfolio designed to improve your organization’s people-centric communications, while reducing your operating costs. It combines an attractive new ergonomic design with “always-on” reliability and secure encrypted communications. The Cisco® IP Phone 7800 Series delivers advanced IP Telephony features and crystal clear wideband audio performance to deliver an easy-to-use, full-featured voice communications experience on Cisco on-premises and hosted infrastructure platforms and third party hosted call control."

Source: www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/unified-ip-phone-7800-series/data-sheet-c78-729488.html


Business recommendation

SEC Consult recommends to update the devices to the newest firmware listed below, where, according to the vendor, the documented issue is fixed.

We want to thank Cisco for the very professional response and great coordination.


Vulnerability overview/description

1) Cleartext Storage of Phone Password

The phone is storing the "phone password", which is needed to access its administrative settings, in cleartext (in multiple locations) in the flash memory.

Because the password is not hashed using a suitable cryptographic hash function and the storage is unencrypted, a physical attacker can easily recover the password and reuse it on other phones, if they are not configured to use unique administrative passwords.


Proof of concept

1) Cleartext Storage of Phone Password

Steps to take:

  • Configure a phone password via the TFTP XML provisioning feature.
  • Desoldering the memory and reading its content.
  • Analyzing the memory content. As example, the Linux command 'strings' can be used below to show the identified password in cleartext in the dumped data.
     
  $ strings nand.dump | grep phonePassword
  phonePassword>sectest</,x
  phonePassword>sectest</,x
  phonePassword>sectest</,x
  phonePassword>sectest</,x


Vulnerable / tested versions

The following firmware/device has been tested:

  • Cisco IP Phone 7821: Firmware version 12.8.1-0001-455

The vendor confirmed that the following devices are affected:

  • Cisco IP Phone 78x1 all releases before firmware version 14.1.1
  • Cisco IP Phone 88x5 all releases before firmware version 14.1.1
  • Cisco IP Phone 88x1 all releases before firmware version 14.1.1
  • Cisco IP Phone 7832 all releases before firmware version 14.1.1
  • Cisco IP Phone 8832 all releases before firmware version 14.1.1
  • Cisco IP Phone 8821 all releases before firmware version 11.0(6)SR2
  • Cisco IP Phone 3905 all releases before firmware version 9.4(1)SR5


Vendor contact timeline

2021-05-19 Contacting vendor through psirt@cisco.com. Set preliminary release date to 2021-08-07. Received PSIRT case number from Cisco employee.
2021-05-20 Cisco states that the finding has been shared with the development team and is currently being analyzed.
2021-06-30 Cisco confirms affected phone models and communicates expected dates for fixed firmware releases.
2021-07-07 New estimated release date was set to 2022-01-31.
2021-12-27 Cisco informs about the fix and the publishing date 2022-01-12 for their advisory
2022-01-13 Coordinated release of the security advisory.

Solution

Update the firmware of the affected devices to the latest available version. 
See the vendor's security advisory for further information:

tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ip-phone-info-disc-fRdJfOxA


Workaround

For immediate mitigation, ensure that phones are configured to use unique administrative passwords.

 

Advisory URL

sec-consult.com/vulnerability-lab/

EOF Gerhard Hechenberger, Steffen Robertz / @2022

 

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