Meta pixel for WordPress <= 2.2.2 - PHP Object Injection
Strategic Overview
- Status
- Patched in 3.0.0
- Affected Plugin
- Meta pixel for WordPress
- Affected Version
<= 2.2.2- CVSS
- 8.1High
- Weakness type
- CWE-502 · Deserialization of Untrusted Data
- CVE
CVE-2021-24217
At a glance
CVE-2021-24217 is a high-severity Deserialization of Untrusted Data vulnerability in the Meta pixel for WordPress WordPress plugin, affecting versions <= 2.2.2. It carries a CVSS score of 8.1 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.0.0; sites on affected versions should update now. Disclosed March 2021, reported by Chloe Chamberland.
Vulnerability Overview
The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data making it possible for PHP objects to be supplied creating an Object Injection vulnerability. There was also a useable magic method in the plugin that could be used to achieve remote code execution.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-502: Deserialization of Untrusted Data
Reaching this weakness in Meta pixel for WordPress <= 2.2.2 takes a caller who can reach the endpoint. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.
A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For Meta pixel for WordPress the fix is 3.0.0: builds <= 2.2.2 are affected, anything from 3.0.0 onward is not.
Remediation
Update to version 3.0.0, or a newer patched version
How does WordSec protect against this?
The attempt arrives as an ordinary request to Meta pixel for WordPress: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Meta pixel for WordPress 3.0.0 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Alerts
External References
Related records
Other vulnerabilities in Meta pixel for WordPress
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