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

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

Unauthenticated PHP Item Injection

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

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

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

Unexpected inputs should be removed. That filtering procedure that keeps out unwanted inputs is called sanitization.

For example, a contact kind must have a function that examines what is sent and block (sterilize) anything that is not text.

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

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

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

The category of the vulnerability is Insecure Deserialization.

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

The description at OWASP:

“The effect of deserialization defects can not be overstated. These defects can result in remote code execution attacks, among the most major attacks possible.The service impact depends on the security requirements of the application and data. “But OWASP likewise keeps in mind that exploiting this type of vulnerability tends to be difficult:”Exploitation of deserialization is rather hard,

as off the shelf exploits hardly ever work without changes or tweaks to the underlying 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)notes the repair as an improvement for security. Users of the Stop Spam Security plugin must think about updating to the latest

variation in order to prevent a hacker from exploiting the plugin. Check out the official notice at the United States Federal Government National Vulnerability Database

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

Stop Spammers Security