A WordPress anti-spam plugin with over 60,000 installations patched a PHP Item injection vulnerability that emerged from improper sanitization of inputs, consequently enabling base64 encoded user input.
Unauthenticated PHP Object Injection
A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Comments, Forms WordPress plugin.
The purpose 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 only enable particular inputs, like text, images, e-mail addresses, whatever input is expected.
Unexpected inputs need to be filtered out. That filtering process that stays out unwanted inputs is called sanitization.
For instance, a contact type must have a function that checks what is sent and block (sanitize) anything that is not text.
The vulnerability found in the anti-spam plugin allowed encoded input (base64 encoded) which can then trigger a type of vulnerability called a PHP Things 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 2nd difficulty, which could lead to PHP Things injection if a plugin set up on the blog site has an appropriate gizmo chain …”
The category of the vulnerability is Insecure Deserialization.
The non-profit Open Web Application Security Project (OWASP) describes the prospective effect of these kinds of vulnerabilities as severe, which may or might not be the case specific to this vulnerability.
The description at OWASP:
“The effect of deserialization flaws can not be overstated. These defects can result in remote code execution attacks, one of the most severe attacks possible.The service effect depends on the security requirements of the application and data. “But OWASP also keeps in mind that exploiting this kind of vulnerability tends to be hard:”Exploitation of deserialization is rather difficult,
as off the rack exploits hardly ever work without changes or tweaks to the underlying exploit code.”The vulnerability in the Stop Spammers Security WordPress
plugin was fixed in version 2022.6 The official Stop Spammers Security changelog (a description with dates of various updates)keeps in mind the repair as an enhancement for security. Users of the Stop Spam Security plugin should think about upgrading to the most recent
version in order to avoid a hacker from making use of the plugin. Read the official notification 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