A WordPress anti-spam plugin with over 60,000 setups patched a PHP Item injection vulnerability that occurred from inappropriate sanitization of inputs, subsequently permitting base64 encoded user input.
Unauthenticated PHP Item Injection
A vulnerability was found in the popular Stop Spammers Security|Block Spam Users, Remarks, Kinds 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 required practice for any WordPress plugin or kind that accepts a user input to only permit specific inputs, like text, images, email addresses, whatever input is anticipated.
Unexpected inputs should be filtered out. That filtering process that keeps out undesirable inputs is called sanitization.
For instance, a contact type must have a function that examines what is sent 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 Object injection vulnerability.
The description of the vulnerability released on the WPScan website explains the problem as:
“The plugin passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as 2nd difficulty, which might cause PHP Things injection if a plugin set up 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 possible impact of these type of vulnerabilities as major, which may or may not be the case particular to this vulnerability.
The description at OWASP:
“The effect of deserialization flaws can not be overemphasized. These flaws can lead to remote code execution attacks, one of the most severe attacks possible.The organization effect depends on the defense requirements of the application and data. “But OWASP likewise notes that exploiting this type of vulnerability tends to be tough:”Exploitation of deserialization is somewhat hard,
as off the shelf exploits hardly ever work without changes 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 numerous updates)notes the repair as an improvement for security. Users of the Stop Spam Security plugin ought to think about updating to the current
variation in order to prevent a hacker from exploiting the plugin. Read the official alert at the United States Federal Government National Vulnerability Database
: CVE-2022-4120 Detail Check out the WPScan publication of details connected to this vulnerability:
Stop Spammers Security