WordPress Anti-Spam Plugin Vulnerability Affects As Much As 60,000+ Websites

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A WordPress anti-spam plugin with over 60,000 setups patched a PHP Object injection vulnerability that emerged from improper sanitization of inputs, subsequently enabling base64 encoded user input.

Unauthenticated PHP Object Injection

A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Remarks, Kinds WordPress plugin.

The purpose of the plugin is to stop spam in remarks, types, and sign-up registrations. It can stop spam bots and has the capability for users to input IP addresses to block.

It is a required practice for any WordPress plugin or type that accepts a user input to only allow particular inputs, like text, images, email addresses, whatever input is anticipated.

Unexpected inputs need to be strained. That filtering procedure that stays out undesirable inputs is called sanitization.

For example, a contact form need to have a function that inspects what is sent and block (sanitize) anything that is not text.

The vulnerability found in the anti-spam plugin enabled encoded input (base64 encoded) which can then set off a kind of vulnerability called a PHP Item injection vulnerability.

The description of the vulnerability released on the WPScan site explains the issue as:

“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are utilized as second obstacle, which could cause PHP Object injection if a plugin set up on the blog site has an appropriate gadget chain …”

The classification of the vulnerability is Insecure Deserialization.

The non-profit Open Web Application Security Task (OWASP) explains the possible effect of these kinds of vulnerabilities as major, which might or might not hold true specific to this vulnerability.

The description at OWASP:

“The effect of deserialization flaws can not be overemphasized. These defects can lead to remote code execution attacks, one of the most severe attacks possible.The service impact depends on the defense needs of the application and information. “But OWASP likewise notes that exploiting this kind of vulnerability tends to be hard:”Exploitation of deserialization is rather hard,

as off the rack exploits rarely work without modifications or tweaks to the hidden exploit code.”The vulnerability in the Stop Spammers Security WordPress

plugin was fixed in version 2022.6 The official Stop Spammers Security changelog (a description with dates of different updates)keeps in mind the fix as an improvement for security. Users of the Stop Spam Security plugin should consider upgrading to the latest

variation in order to prevent a hacker from exploiting the plugin. Read the main notice at the United States Government National Vulnerability Database

: CVE-2022-4120 Detail Check out the WPScan publication of information associated with this vulnerability:

Stop Spammers Security