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

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A WordPress anti-spam plugin with over 60,000 installations patched a PHP Item injection vulnerability that arose from improper sanitization of inputs, consequently allowing base64 encoded user input.

Unauthenticated PHP Things Injection

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

The function 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 needed practice for any WordPress plugin or type that accepts a user input to only allow specific inputs, like text, images, e-mail addresses, whatever input is anticipated.

Unexpected inputs ought to be strained. That filtering process that stays out unwanted inputs is called sanitization.

For example, a contact kind need to have a function that checks what is submitted 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 Item 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 cause PHP Object injection if a plugin set up on the blog site has an ideal gadget chain …”

The classification of the vulnerability is Insecure Deserialization.

The non-profit Open Web Application Security Task (OWASP) explains the potential effect of these sort of vulnerabilities as serious, which may or might not be the case particular to this vulnerability.

The description at OWASP:

“The effect of deserialization flaws can not be overstated. These flaws can result in remote code execution attacks, among the most major attacks possible.The organization impact depends on the defense needs of the application and data. “But OWASP also notes that exploiting this sort of vulnerability tends to be challenging:”Exploitation of deserialization is rather 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 fixed in version 2022.6 The main Stop Spammers Security changelog (a description with dates of various updates)keeps in mind the repair as an improvement for security. Users of the Stop Spam Security plugin need to think about upgrading to the most recent

version in order to avoid a hacker from exploiting the plugin. Check out the official alert at the United States Government National Vulnerability Database

: CVE-2022-4120 Detail Read the WPScan publication of information related to this vulnerability:

Stop Spammers Security