Vulnerability Note VU#534407

Barracuda Web Filter insecurely performs SSL inspection

Original Release date: 28 Apr 2015 | Last revised: 28 Apr 2015


Barracuda Web Filter prior to version does not properly check upstream certificate validity when performing SSL inspection, and delivers one of three default root CA certificates across multiple machines for SSL inspection.


According to Barracuda Networks, the Barracuda Web Filter is a "comprehensive solution for web security and management" with many features, including the ability to provide "visibility into SSL-encrypted traffic". This SSL inspection feature of the Barracuda Web Filter is vulnerable to multiple issues.

Incomplete validation of upstream certificate validity - CVE-2015-0961

Barracuda Web Filter versions between 7.0 and do not check upstream certificate validity when performing SSL inspection.

Shared root CA certificate - CVE-2015-0962

Barracuda Web Filter versions between 7.0 and ship one of three different default certificates that are shared across multiple machine for use in the SSL Inspection feature.

  • Users who have configured SSL Inspection on a Barracuda Web Filter may be affected. Beginning in version, Barracuda Web Filter verifies certificate validity and generates a unique default certificate for each appliance.

    Barracuda Networks has released a security advisory with more details. For more information on the impact of these issues on SSL inspection, please see Will Dormann's CERT/CC blog post on SSL Inspection.

    The CVSS score below is based on CVE-2015-0962.

  • Impact

    The impact of either CVE-2015-0961 or CVE-2015-0962 may allow an attacker to successfully achieve a man-in-the-middle (MITM) attack without the client knowing it.


    Update the firmware

    Barracuda Networks has released firmware version on April 16th, 2015 to address these issues. Affected users should upgrade to firmware or later as soon as possible.

    Users who have deployed an affected service using the default certificate supplied with the appliance will need to deploy a new client certificate to their clients and remove the previously deployed certificate. Instructions for deploying and removing client certificates are available at

    Check that old shared certificates are removed

    Barracuda has also provided, a site that will show users if their browser trusts any of the shared default certificates and includes instructions for removing the certificates from the browser trust store if necessary.

    Vendor Information (Learn More)

    VendorStatusDate NotifiedDate Updated
    Barracuda NetworksAffected-21 Apr 2015
    If you are a vendor and your product is affected, let us know.

    CVSS Metrics (Learn More)

    Group Score Vector
    Base 8.8 AV:N/AC:M/Au:N/C:C/I:C/A:N
    Temporal 6.9 E:POC/RL:OF/RC:C
    Environmental 5.2 CDP:ND/TD:M/CR:ND/IR:ND/AR:ND



    Thanks to Barracuda Networks for promptly addressing these issues and contacting the CERT/CC to coordinate disclosure.

    This document was written by Garret Wassermann.

    Other Information

    • CVE IDs: CVE-2015-0961 CVE-2015-0962
    • Date Public: 28 Apr 2015
    • Date First Published: 28 Apr 2015
    • Date Last Updated: 28 Apr 2015
    • Document Revision: 27


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