A WordPress anti-spam plugin with over 60,000 setups patched a PHP Things injection vulnerability that emerged from inappropriate sanitization of inputs, subsequently allowing base64 encoded user input.
Unauthenticated PHP Item Injection
A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Remarks, Kinds WordPress plugin.
The function of the plugin is to stop spam in comments, types, 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 type that accepts a user input to just permit specific inputs, like text, images, e-mail addresses, whatever input is anticipated.
Unanticipated inputs must be removed. That filtering procedure that stays out unwanted inputs is called sanitization.
For example, a contact form should have a function that checks what is sent and block (sanitize) anything that is not text.
The vulnerability discovered in the anti-spam plugin allowed encoded input (base64 encoded) which can then activate a type of vulnerability called a PHP Item injection vulnerability.
The description of the vulnerability released on the WPScan website describes the concern as:
“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as 2nd challenge, which might lead to 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 Job (OWASP) explains the potential effect of these type of vulnerabilities as severe, which may or might not be the case specific to this vulnerability.
The description at OWASP:
“The impact of deserialization defects can not be overemphasized. These flaws can result in remote code execution attacks, among the most major attacks possible.The business impact depends on the security requirements of the application and information. “But OWASP also notes that exploiting this type of vulnerability tends to be challenging:”Exploitation of deserialization is somewhat challenging,
as off the rack exploits seldom work without modifications or tweaks to the hidden exploit code.”The vulnerability in the Stop Spammers Security WordPress
plugin was repaired in version 2022.6 The main 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 upgrading to the latest
variation in order to avoid a hacker from exploiting the plugin. Check out the main alert at the United States Federal Government National Vulnerability Database
: CVE-2022-4120 Information Read the WPScan publication of information associated with this vulnerability:
Stop Spammers Security