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             AUSCERT External Security Bulletin Redistribution

      The BIG-IP CFE logs sensitive Azure storage account credentials
                             19 November 2020


        AusCERT Security Bulletin Summary

Product:           BIG-IP Products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Modify Arbitrary Files   -- Existing Account
                   Access Confidential Data -- Existing Account
                   Reduced Security         -- Existing Account
Resolution:        Patch/Upgrade

Original Bulletin: 

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K21125762: The BIG-IP CFE logs sensitive Azure storage account credentials

Original Publication Date: 18 Nov, 2020

Security Advisory Description

The BIG-IP Cloud Failover Extension (CFE) logs sensitive Azure storage account
credentials in /var/log/restnoded/restnoded.log.

This issue occurs when all of the following conditions are met:

  o You configure the CFE to provide failover functionality for your BIG-IP
    systems in Azure. For more information on CFE, refer to CFE Overview on
  o You increase the CFE logging level on the BIG-IP system to Silly. The
    default value is Info. For more information, refer to Logging in CloudDocs.


A malicious user who has access to the BIG-IP system log files can use the
leaked storage account name and access key to access your Azure storage to
read, write, or delete files.


As a result of this issue, you may encounter the following symptom:

  o You observe your Azure account name and access key logged in the /var/log/
    restnoded/restnoded.log file on the BIG-IP system.

Security Advisory Status

F5 Product Development has assigned ID 964813 to this issue. F5 has confirmed
that this issue exists in the products listed in the Applies to (see versions)
box, located in the upper-right corner of this article. For information about
releases, point releases, or hotfixes that resolve this issue, refer to the
following table.

|Type of fix             |Fixes introduced in|Related articles       |
|Release                 |None               |None                   |
|Point release/hotfix    |None               |None                   |
|Cloud Failover Extension|1.6.1              |Cloud Failover Releases|

Security Advisory Recommended Actions


To eliminate this issue, you can upgrade to a version listed in the Fixes
introduced in column and delete the log files containing the Azure credentials.
Additionally, if you suspect that the Storage Account name and keys have been
exposed to untrusted users, you should regenerate the Azure Storage Account
access key and reset the CFE on the BIG-IP system.

Impact of workaround: Performing the following procedures updates and resets
the CFE. F5 recommends that you perform these procedures during a scheduled
maintenance window.

  o Upgrade the CFE
  o Delete the log files containing the Azure credentials.
  o Regenerate the Azure Storage Account access key.^1
  o Reset the CFE on the BIG-IP system^1

^1Perform this procedure when you suspect that the Storage Account name and
keys have been exposed to untrusted users.

Upgrade the CFE

To upgrade the CFE, download the CFE package from GitHub and upload and install
the package on the BIG-IP systems. For more information, refer to Download and
Install Cloud Failover Extension. 

Delete the log files containing the Azure credentials

Delete the log files /var/log/restnoded/restnoded* containing the Azure account
credentials on the affected BIG-IP system.

Regenerate the Azure Storage Account access key

To regenerate your access key, refer to Manage storage account access keys and
Storage Accounts - Regenerate Key.

Note: These links take you to a resource outside of AskF5, and it is possible
that the document may be removed without our knowledge.

Reset the CFE on the BIG-IP system

To reset the CFE on your BIG-IP systems, you can send a "resetStateFile": true
json content to the /reset REST endpoint. You can use a command such as curl,
as shown in the following example:

curl --header "Content-Type: application/json" --request POST --data '
{"resetStateFile": true}' -ku example_user:example_password https://:

For more information on the /reset endpoint, refer to the API Reference

Supplemental Information

o K51812227: Understanding security advisory versioning
  o K41942608: Overview of AskF5 security advisory articles
  o K4602: Overview of the F5 security vulnerability response policy
  o K4918: Overview of the F5 critical issue hotfix policy
  o K9502: BIG-IP hotfix and point release matrix
  o K13123: Managing BIG-IP product hotfixes (11.x - 16.x)
  o K167: Downloading software and firmware from F5
  o K9970: Subscribing to email notifications regarding F5 products
  o K9957: Creating a custom RSS feed to view new and updated documents

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