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

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

Unauthenticated PHP Object Injection

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

The function of the plugin is to stop spam in remarks, forms, and sign-up registrations. It can stop spam bots and has the ability 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 just enable particular inputs, like text, images, email addresses, whatever input is anticipated.

Unforeseen inputs should be strained. That filtering procedure that keeps out unwanted inputs is called sanitization.

For example, a contact form need to 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 problem as:

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

The classification of the vulnerability is Insecure Deserialization.

The non-profit Open Web Application Security Project (OWASP) describes the potential impact of these type of vulnerabilities as severe, which might or may not be the case particular to this vulnerability.

The description at OWASP:

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

as off the rack makes use of seldom work without changes or tweaks to the hidden exploit code.”The vulnerability in the Stop Spammers Security WordPress

plugin was repaired in version 2022.6 The main Stop Spammers Security changelog (a description with dates of different updates)notes the repair as an improvement for security. Users of the Stop Spam Security plugin must think about updating to the most recent

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

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

Stop Spammers Security