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 installations covered a PHP Object injection vulnerability that arose from incorrect sanitization of inputs, consequently allowing base64 encoded user input.

Unauthenticated PHP Things Injection

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

The purpose of the plugin is to stop spam in comments, 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 enable particular inputs, like text, images, email addresses, whatever input is expected.

Unforeseen inputs need to be filtered out. That filtering procedure that keeps out unwanted inputs is called sanitization.

For instance, a contact kind should have a function that checks what is sent and block (sterilize) anything that is not text.

The vulnerability discovered in the anti-spam plugin enabled encoded input (base64 encoded) which can then activate a kind of vulnerability called a PHP Object injection vulnerability.

The description of the vulnerability published on the WPScan site describes the concern as:

“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as second difficulty, which could result in PHP Object injection if a plugin installed on the blog has an ideal gadget chain …”

The category of the vulnerability is Insecure Deserialization.

The non-profit Open Web Application Security Job (OWASP) describes the potential effect of these type of vulnerabilities as major, which might or might not be the case specific to this vulnerability.

The description at OWASP:

“The impact of deserialization defects can not be overstated. These flaws can result in remote code execution attacks, one of the most serious attacks possible.The business effect depends upon the security needs of the application and information. “But OWASP also keeps in mind that exploiting this type of vulnerability tends to be challenging:”Exploitation of deserialization is somewhat difficult,

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

plugin was repaired in variation 2022.6 The official Stop Spammers Security changelog (a description with dates of various updates)keeps in mind the repair as an enhancement for security. Users of the Stop Spam Security plugin should think about updating to the most recent

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

: CVE-2022-4120 Information Check out the WPScan publication of information connected to this vulnerability:

Stop Spammers Security