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

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A WordPress anti-spam plugin with over 60,000 setups covered a PHP Object injection vulnerability that developed from improper sanitization of inputs, subsequently enabling base64 encoded user input.

Unauthenticated PHP Object Injection

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

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

It is a required practice for any WordPress plugin or form that accepts a user input to only permit particular inputs, like text, images, e-mail addresses, whatever input is expected.

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

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

The vulnerability found in the anti-spam plugin permitted encoded input (base64 encoded) which can then set off 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 utilized as second challenge, which could result in PHP Object injection if a plugin installed on the blog site has an ideal gadget chain …”

The classification of the vulnerability is Insecure Deserialization.

The non-profit Open Web Application Security Project (OWASP) explains the prospective effect of these type of vulnerabilities as major, 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 lead to remote code execution attacks, among the most major attacks possible.The business impact depends on the security needs of the application and data. “However OWASP also 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 hardly ever work without changes or tweaks to the underlying exploit code.”The vulnerability in the Stop Spammers Security WordPress

plugin was fixed in variation 2022.6 The official 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 need to consider updating to the current

variation in order to prevent a hacker from exploiting the plugin. Check out the main alert 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