Millions of WordPress sites targeted by File Manager zero-day

A dramatic surge in attacks saw one million sites targeted on 4 September alone

More than 1.7 million sites designed on the WordPress platform have been attacked due to a zero-day vulnerability in the File Manager plugin, with hundreds of thousands more sites likely to be under threat.

Attacks against a flaw in the File Manager plugin surged dramatically towards the end of last week, according to researchers with the Wordfence security plugin, with attacks against one million sites on 4 September alone.

Hackers have been exploiting the flaw in the wild by executing commands to upload malicious files onto target WordPress sites. Analysis by Wordfence’s threat intelligence team showed it was also possible to bypass the in-built file upload protection mechanism.

Although a patch has been released, labelled as version 6.9 of the plugin, as of last Friday there were still 261,800 sites running a vulnerable form of File Manager. Sites not using the plugin are still being probed by bots seeking to exploit vulnerable versions of the app. 

Of the three million WordPress sites that Wordfence protects, 1.7 million have been probed for the vulnerability, meaning the true extent of the exploitation is unknown and likely much higher than reported figures.

File Manager is designed to help administrators manage files on their sites, and offers an additional library known as elFinder which is an open-source file manager designed to provide a simple user interface. 

The issue centres on the File Manager plugin renaming the extension on the elFinder library 'connector.minimal.php.dist' file to '.php', meaning it can be executed directly - even though the connector file isn’t used by File Manager itself. The file had no direct access restrictions, meaning it could be accessed by anyone. 

The attacks that Wordfence researchers have seen in the wild involved hackers using the upload command to upload PHP files containing webshells hidden in an image.

Beyond applying the patch, Wordpress users are being offered an extra layer of protection thanks to an additional firewall rule that prevents all access to ‘connector.minimal.php’.

Wordfence has also recommended that users not actively using the plugin should uninstall it completely to avoid any risk.

Featured Resources

2021 Thales cloud security study

The challenges of cloud data protection and access management in a hybrid and multi cloud world

Free download

IDC agility assessment

The competitive advantage in adaptability

Free Download

Digital transformation insights from CIOs for CIOs

Transformation pilotes, co-pilots, and engineers

Free download

What ITDMs did next - and what they should be doing now

Enable continued collaboration and communication for hybrid workers

Recommended

Kaspersky exposes MysterySnail zero-day exploit in Windows
zero-day exploit

Kaspersky exposes MysterySnail zero-day exploit in Windows

13 Oct 2021

Most Popular

What should you really be asking about your remote access software?
Sponsored

What should you really be asking about your remote access software?

17 Nov 2021
How to move Microsoft's Windows 11 from a hard drive to an SSD
Microsoft Windows

How to move Microsoft's Windows 11 from a hard drive to an SSD

24 Nov 2021
Nike to take customers into the metaverse with 'NIKELAND'
virtualisation

Nike to take customers into the metaverse with 'NIKELAND'

19 Nov 2021