A WordPress anti-spam plugin with over 60,000 setups covered a PHP Item injection vulnerability that emerged from incorrect sanitization of inputs, subsequently enabling base64 encoded user input.
Unauthenticated PHP Object Injection
A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Remarks, Forms WordPress plugin.
The function of the plugin is to stop spam in comments, 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 type that accepts a user input to only permit specific inputs, like text, images, e-mail addresses, whatever input is anticipated.
Unanticipated inputs ought to be filtered out. That filtering procedure that stays out unwanted inputs is called sanitization.
For instance, a contact kind must have a function that checks 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 type of vulnerability called a PHP Things injection vulnerability.
The description of the vulnerability released on the WPScan website describes the problem as:
“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as second challenge, which could result in PHP Item injection if a plugin installed on the blog site has an ideal gizmo chain …”
The classification of the vulnerability is Insecure Deserialization.
The non-profit Open Web Application Security Task (OWASP) explains the potential effect of these type of vulnerabilities as serious, which may or might not be the case particular to this vulnerability.
The description at OWASP:
“The effect of deserialization defects can not be overstated. These flaws can lead to remote code execution attacks, among the most serious attacks possible.The organization effect depends upon the security needs of the application and data. “But OWASP also notes that exploiting this kind of vulnerability tends to be hard:”Exploitation of deserialization is somewhat hard,
as off the shelf makes use of seldom work without modifications or tweaks to the hidden 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 different updates)keeps in mind the fix as an improvement for security. Users of the Stop Spam Security plugin need to consider upgrading to the current
variation in order to avoid a hacker from exploiting the plugin. Check out the main alert at the United States Government National Vulnerability Database
: CVE-2022-4120 Detail Check out the WPScan publication of details connected to this vulnerability:
Stop Spammers Security