A WordPress anti-spam plugin with over 60,000 installations patched a PHP Item injection vulnerability that emerged from incorrect sanitization of inputs, consequently enabling base64 encoded user input.
Unauthenticated PHP Item Injection
A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Comments, Forms 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 kind that accepts a user input to only permit particular inputs, like text, images, e-mail addresses, whatever input is anticipated.
Unforeseen inputs need to be strained. That filtering process that keeps out undesirable inputs is called sanitization.
For example, a contact kind should have a function that inspects what is sent and block (sterilize) anything that is not text.
The vulnerability found in the anti-spam plugin allowed encoded input (base64 encoded) which can then set off a type of vulnerability called a PHP Item injection vulnerability.
The description of the vulnerability published on the WPScan site describes the issue as:
“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as second challenge, which might lead to PHP Object injection if a plugin installed on the blog has an ideal gizmo chain …”
The classification of the vulnerability is Insecure Deserialization.
The non-profit Open Web Application Security Project (OWASP) explains the prospective impact of these type of vulnerabilities as severe, which may or may not hold true particular to this vulnerability.
The description at OWASP:
“The effect of deserialization flaws can not be overemphasized. These defects can lead to remote code execution attacks, among the most major attacks possible.The service impact depends upon the defense requirements of the application and information. “However OWASP likewise notes that exploiting this type of vulnerability tends to be challenging:”Exploitation of deserialization is somewhat challenging,
as off the rack exploits hardly ever work without changes or tweaks to the underlying make use of code.”The vulnerability in the Stop Spammers Security WordPress
plugin was fixed in variation 2022.6 The official Stop Spammers Security changelog (a description with dates of numerous updates)notes the repair as an enhancement for security. Users of the Stop Spam Security plugin need to think about upgrading to the most recent
variation in order to prevent a hacker from exploiting the plugin. Read the main notification at the United States Federal Government National Vulnerability Database
: CVE-2022-4120 Detail Read the WPScan publication of details related to this vulnerability:
Stop Spammers Security