CVE-2021-24280

Redirection for Contact Form 7 <= 2.3.3 - Authenticated PHP Object Injection

2021-04-20 00:00
Chloe Chamberland

Strategic Overview

Status
Patched in 2.3.4
Affected Plugin
Redirection for Contact Form 7
Affected Version
< 2.3.4
CVSS
8.8High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2021-24280
View all Redirection for Contact Form 7 vulnerabilities

At a glance

CVE-2021-24280 is a high-severity Deserialization of Untrusted Data vulnerability in the Redirection for Contact Form 7 WordPress plugin, affecting versions < 2.3.4. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account. The issue is fixed in version 2.3.4; sites on affected versions should update now. Disclosed April 2021, reported by Chloe Chamberland.

Vulnerability Overview

In the Redirection for Contact Form 7 WordPress plugin before 2.3.4, any authenticated user, such as a subscriber, could use the import_from_debug AJAX action to inject PHP objects.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, 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 Redirection for Contact Form 7 < 2.3.4 takes any authenticated account. 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 Redirection for Contact Form 7 the fix is 2.3.4: builds < 2.3.4 are affected, anything from 2.3.4 onward is not.

Remediation

Update to version 2.3.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Redirection for Contact Form 7: 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: Redirection for Contact Form 7 2.3.4 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24280https://www.wordfence.com/threat-intel/vulnerabilities/id/774afb96-4385-4693-a446-c87f81b39febhttps://nvd.nist.gov/vuln/detail/CVE-2021-24280

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C