ASB-2018.0041 - [Win][UNIX/Linux] WordPress: Reduced security - Existing account - 2018-02-09


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                         AUSCERT Security Bulletin

                               ASB-2018.0041
                 WordPress Autoupdate Regression in 4.9.3
                              9 February 2018

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:              WordPress
Operating System:     UNIX variants (UNIX, Linux, OSX)
                      Windows
Impact/Access:        Reduced Security -- Existing Account
Resolution:           Patch/Upgrade
Member content until: Sunday, March 11 2018

OVERVIEW

        WordPress has announced a bug in version 4.9.3 which breaks the 
        automatic update feature. [1]


IMPACT

        The vendor has provided the following information:
        
        "WordPress 4.9.4 is now available.
        
        This maintenance release fixes a severe bug in 4.9.3, which will cause sites
        that support automatic background updates to fail to update automatically, and
        will require action from you (or your host) for it to be updated to 4.9.4.
        
        Four years ago with WordPress 3.7 "Basie", we added the ability for WordPress to
        self-update, keeping your website secure and bug-free, even when you weren't
        available to do it yourself. For four years it's helped keep millions of
        installs updated with very few issues over that time. Unfortunately yesterdays
        4.9.3 release contained a severe bug which was only discovered after release.
        The bug will cause WordPress to encounter an error when it attempts to update
        itself to WordPress 4.9.4, and will require an update to be performed through
        the WordPress dashboard or hosts update tools.
        
        WordPress managed hosting companies who install updates automatically for their
        customers can install the update as normal, and we'll be working with other
        hosts to ensure that as many customers of theirs who can be automatically
        updated to WordPress 4.9.4 can be.
        
        For more technical details of the issue, we've posted on our Core Development
        blog. For a full list of changes, consult the list of tickets.
        
        Download WordPress 4.9.4 or visit Dashboard -> Updates and click "Update Now.""
	[1]


MITIGATION

        WordPress advises that users will need to upgrade to version 4.9.4 
        manually in order restore automatic updates. [1]


REFERENCES

        [1] WordPress 4.9.4 Maintenance Release
            https://wordpress.org/news/2018/02/wordpress-4-9-4-maintenance-release/

AusCERT has made every effort to ensure that the information contained
in this document is accurate.  However, the decision to use the information
described is the responsibility of each user or organisation. The decision to
follow or act on information or advice contained in this security bulletin is
the responsibility of each user or organisation, and should be considered in
accordance with your organisation's site policies and procedures. AusCERT
takes no responsibility for consequences which may arise from following or
acting on information or advice contained in this security bulletin.

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Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours 
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
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