A WordPress anti-spam plugin with over 60,000 installations patched a PHP Object injection vulnerability that developed from improper sanitization of inputs, subsequently allowing base64 encoded user input.
Unauthenticated PHP Things 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 remarks, 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 needed practice for any WordPress plugin or form that accepts a user input to just permit specific inputs, like text, images, e-mail addresses, whatever input is anticipated.
Unanticipated inputs should be strained. That filtering procedure that keeps out unwanted inputs is called sanitization.
For example, a contact form should have a function that examines what is sent and block (sanitize) anything that is not text.
The vulnerability discovered in the anti-spam plugin permitted encoded input (base64 encoded) which can then trigger a type of vulnerability called a PHP Things injection vulnerability.
The description of the vulnerability published 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 obstacle, which could lead to PHP Item injection if a plugin installed on the blog has an ideal device chain …”
The category of the vulnerability is Insecure Deserialization.
The non-profit Open Web Application Security Task (OWASP) explains the possible effect of these type of vulnerabilities as severe, which may or might not be the case particular 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 organization effect depends on the protection requirements of the application and information. “However OWASP also notes that exploiting this sort of vulnerability tends to be difficult:”Exploitation of deserialization is somewhat challenging,
as off the rack makes use of 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 official Stop Spammers Security changelog (a description with dates of various updates)notes the fix as an enhancement for security. Users of the Stop Spam Security plugin should think about updating to the most recent
version in order to prevent a hacker from exploiting the plugin. Read the main notice 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