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

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

Unauthenticated PHP Things Injection

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

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

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

Unanticipated inputs should be strained. That filtering process that keeps out undesirable inputs is called sanitization.

For example, a contact form need to have a function that examines what is submitted and block (sterilize) anything that is not text.

The vulnerability discovered in the anti-spam plugin enabled encoded input (base64 encoded) which can then trigger a kind of vulnerability called a PHP Item 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 2nd obstacle, which might cause PHP Item injection if a plugin installed on the blog site has an appropriate gadget chain …”

The category of the vulnerability is Insecure Deserialization.

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

The description at OWASP:

“The effect of deserialization defects can not be overemphasized. These defects can lead to remote code execution attacks, one of the most major attacks possible.The company impact depends upon the defense needs of the application and information. “But OWASP likewise keeps in mind that exploiting this kind of vulnerability tends to be hard:”Exploitation of deserialization is rather hard,

as off the shelf exploits rarely work without changes or tweaks to the underlying make use of 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 numerous updates)notes the repair as an enhancement for security. Users of the Stop Spam Security plugin should consider upgrading to the most recent

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

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

Stop Spammers Security