A WordPress anti-spam plugin with over 60,000 installations patched a PHP Things injection vulnerability that emerged from incorrect 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, Remarks, Types WordPress plugin.
The function 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 block.
It is a required practice for any WordPress plugin or form that accepts a user input to just permit specific inputs, like text, images, email addresses, whatever input is anticipated.
Unexpected inputs ought to be removed. That filtering procedure that keeps out unwanted inputs is called sanitization.
For instance, a contact kind must have a function that examines what is submitted and block (sanitize) anything that is not text.
The vulnerability discovered in the anti-spam plugin enabled encoded input (base64 encoded) which can then activate a type 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 second difficulty, which could cause PHP Item injection if a plugin installed on the blog site has an appropriate device chain …”
The classification of the vulnerability is Insecure Deserialization.
The non-profit Open Web Application Security Job (OWASP) explains the prospective impact of these type of vulnerabilities as severe, which may or might not be the case particular to this vulnerability.
The description at OWASP:
“The impact of deserialization defects can not be overemphasized. These defects can cause remote code execution attacks, among the most severe attacks possible.The business impact depends upon the security needs of the application and data. “However OWASP likewise keeps in mind that exploiting this kind of vulnerability tends to be tough:”Exploitation of deserialization is somewhat difficult,
as off the shelf exploits rarely work without modifications 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 different updates)keeps in mind the repair as an enhancement for security. Users of the Stop Spam Security plugin must think about updating to the current
version in order to prevent a hacker from exploiting the plugin. Read the official notification at the United States Federal Government National Vulnerability Database
: CVE-2022-4120 Information Check out the WPScan publication of details associated with this vulnerability:
Stop Spammers Security