Ransomware has become a popular attack vector with a well-known execution strategy: Infect a user’s computer, encrypt all files and scramble the names, then ask for money in exchange for the decryption key.

According to Naked Security, however, the game is changing: A new form of PHP ransomware skips the local device part of the infection and instead goes straight for Web servers. The result? Virtually any site that hosts content is under threat. Here’s a look at the newest ransomware roll out.

PHP Ransomware in the Locker Room

As noted by PCWorld, this new ransomware is known as CTB Locker, which is the same as one of the most widespread Windows ransomware attacks. While there’s no confirmation that the two are related, initial reports indicated that this new CTB Locker could have a similarly substantial impact.

Most content management systems, including WordPress, Joomla and Drupal, use the PHP programming language to produce dynamically generated content. But there’s a problem: Before any Web page is sent out by its server, PHP scripts are executed. If attackers can insert a new index.php, they can take control of all server-side PHP scripts and can do whatever they like with website content.

Attackers could gain access by stealing website login credentials or by using servers containing unpatched plugins that permit users to modify files that should be protected. Once infected, cybercriminals can leave their code until they submit a specific upload request. This starts the encryption process and generates two passwords — one for a set of uploaded test files and one to decrypt the entire website.

Hacked sites are told to pay up 0.4 bitcoin (around $170) and are also provided a handy chat window to communicate “questions or suggestions” to the PHP ransomware developers. It’s also worth noting that the new CTB Locker doesn’t discriminate since both Linux and Windows servers are equally vulnerable.

Public Knowledge

Aside from relatively strong encryption and a somewhat original approach — CTB Locker was likely modeled after the Linux.Encoder.1 website ransomware found in November 2015 — this new PHP malware also comes with the specter of public embarrassment. While it might be possible to hide the encryption of a local Windows or Linux machine, CTB Locker displays a message to all visitors informing them that the website has been compromised.

It’s a good idea on the part of malware-makers; widespread knowledge of security compromise is one of the quickest ways to convince victims they should pony up the cash. Staying safe amounts to paying attention: Don’t pick a weak password, always use two-factor authentication, review access permissions to make sure guests can’t modify files, run a real-time antivirus scan and make sure the server itself isn’t running any unpatched apps.

Bottom line? Ransomware isn’t going away. As security professionals get better at dealing with local infections, criminals have taken their efforts online to lock down valuable Web content and make their conquests public knowledge.