WordPress Anti-Spam Plugin Vulnerability Impacts Up To 60,000+ Websites

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A WordPress anti-spam plugin with over 60,000 setups covered a PHP Item injection vulnerability that occurred from inappropriate sanitization of inputs, consequently permitting base64 encoded user input.

Unauthenticated PHP Item Injection

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

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

It is a needed practice for any WordPress plugin or form that accepts a user input to just permit particular inputs, like text, images, email addresses, whatever input is expected.

Unforeseen inputs should be strained. That filtering process that stays out unwanted inputs is called sanitization.

For instance, a contact form must have a function that examines what is sent and block (sanitize) anything that is not text.

The vulnerability found in the anti-spam plugin permitted encoded input (base64 encoded) which can then trigger a type of vulnerability called a PHP Object injection vulnerability.

The description of the vulnerability released on the WPScan website describes the issue as:

“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as 2nd challenge, which might result in PHP Item injection if a plugin installed on the blog site has a suitable gizmo chain …”

The classification of the vulnerability is Insecure Deserialization.

The non-profit Open Web Application Security Task (OWASP) explains the possible impact of these kinds of vulnerabilities as severe, which may or may not be the case specific to this vulnerability.

The description at OWASP:

“The effect of deserialization flaws can not be overemphasized. These defects can cause remote code execution attacks, one of the most severe attacks possible.The company impact depends on the protection requirements of the application and information. “However OWASP likewise keeps in mind that exploiting this kind of vulnerability tends to be difficult:”Exploitation of deserialization is somewhat hard,

as off the shelf exploits seldom work without modifications or tweaks to the underlying exploit code.”The vulnerability in the Stop Spammers Security WordPress

plugin was repaired in version 2022.6 The official Stop Spammers Security changelog (a description with dates of numerous updates)notes the fix as an improvement for security. Users of the Stop Spam Security plugin ought to consider upgrading to the current

variation in order to avoid a hacker from making use of the plugin. Check out the main notification at the United States Government National Vulnerability Database

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

Stop Spammers Security