A WordPress anti-spam plugin with over 60,000 setups patched a PHP Item injection vulnerability that occurred from improper sanitization of inputs, subsequently enabling base64 encoded user input.
Unauthenticated PHP Item Injection
A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Comments, Types WordPress plugin.
The purpose 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 obstruct.
It is a needed practice for any WordPress plugin or form that accepts a user input to just allow specific inputs, like text, images, e-mail addresses, whatever input is anticipated.
Unanticipated inputs ought to be filtered out. That filtering process that keeps out undesirable inputs is called sanitization.
For example, a contact form should have a function that checks what is sent and block (sterilize) anything that is not text.
The vulnerability found in the anti-spam plugin enabled encoded input (base64 encoded) which can then activate a kind of vulnerability called a PHP Item injection vulnerability.
The description of the vulnerability released 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 second challenge, which might result in PHP Object injection if a plugin installed on the blog has a suitable gadget 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 serious, which might or might not hold true particular to this vulnerability.
The description at OWASP:
“The effect of deserialization flaws can not be overstated. These flaws can lead to remote code execution attacks, among the most severe attacks possible.The organization impact depends upon the security requirements of the application and information. “But OWASP likewise keeps in mind that exploiting this type of vulnerability tends to be hard:”Exploitation of deserialization is somewhat tough,
as off the rack exploits hardly ever work without modifications or tweaks to the underlying 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 various updates)notes the repair as an enhancement for security. Users of the Stop Spam Security plugin ought to consider updating to the latest
variation in order to avoid a hacker from making use of the plugin. Check out the official notice at the United States Government National Vulnerability Database
: CVE-2022-4120 Detail Check out the WPScan publication of details associated with this vulnerability:
Stop Spammers Security