A WordPress anti-spam plugin with over 60,000 installations patched a PHP Things injection vulnerability that arose from incorrect sanitization of inputs, consequently allowing base64 encoded user input.
Unauthenticated PHP Things Injection
A vulnerability was found in the popular Stop Spammers Security|Block Spam Users, Comments, Kinds WordPress plugin.
The purpose of the plugin is to stop spam in remarks, kinds, and sign-up registrations. It can stop spam bots and has the capability 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 just enable specific inputs, like text, images, email addresses, whatever input is anticipated.
Unforeseen inputs must be removed. That filtering process that keeps out undesirable inputs is called sanitization.
For instance, a contact type must have a function that inspects what is submitted and block (sanitize) 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 Things injection vulnerability.
The description of the vulnerability released on the WPScan website explains the concern as:
“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as second obstacle, which could lead to PHP Things injection if a plugin installed on the blog has an appropriate device chain …”
The classification of the vulnerability is Insecure Deserialization.
The non-profit Open Web Application Security Task (OWASP) describes the possible impact of these sort of vulnerabilities as severe, which might or may not hold true 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, one of the most serious attacks possible.The company effect depends on the security requirements of the application and data. “But OWASP also notes that exploiting this type of vulnerability tends to be tough:”Exploitation of deserialization is rather hard,
as off the rack exploits hardly ever work without modifications or tweaks to the underlying make use of 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)notes the fix as an improvement for security. Users of the Stop Spam Security plugin ought to think about updating to the most recent
variation in order to avoid a hacker from exploiting the plugin. Check out the main notification at the United States Federal Government National Vulnerability Database
: CVE-2022-4120 Detail Read the WPScan publication of details associated with this vulnerability:
Stop Spammers Security