A WordPress anti-spam plugin with over 60,000 installations patched a PHP Things injection vulnerability that emerged from inappropriate sanitization of inputs, consequently enabling base64 encoded user input.
Unauthenticated PHP Things Injection
A vulnerability was discovered in the popular Stop Spammers Security|Block Spam Users, Comments, Forms WordPress plugin.
The purpose of the plugin is to stop spam in remarks, types, and sign-up registrations. It can stop spam bots and has the ability for users to input IP addresses to block.
It is a needed practice for any WordPress plugin or type that accepts a user input to only permit particular inputs, like text, images, e-mail addresses, whatever input is anticipated.
Unexpected inputs should be strained. That filtering procedure that stays out undesirable inputs is called sanitization.
For example, a contact form need to have a function that examines what is sent and block (sterilize) anything that is not text.
The vulnerability found in the anti-spam plugin permitted 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 site 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 cause PHP Object 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 Task (OWASP) describes the possible impact of these type of vulnerabilities as severe, which might or may not be the case specific to this vulnerability.
The description at OWASP:
“The effect of deserialization flaws can not be overstated. These flaws can cause remote code execution attacks, one of the most severe attacks possible.The organization impact depends on the protection needs of the application and data. “However OWASP likewise notes that exploiting this sort of vulnerability tends to be tough:”Exploitation of deserialization is rather hard,
as off the rack exploits hardly ever work without modifications or tweaks to the hidden make use of code.”The vulnerability in the Stop Spammers Security WordPress
plugin was repaired in variation 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 should consider upgrading to the current
version in order to avoid a hacker from exploiting the plugin. Check out the main notification at the United States Government National Vulnerability Database
: CVE-2022-4120 Information Read the WPScan publication of information connected to this vulnerability:
Stop Spammers Security