CVE-2024-1792

CMB2 <= 2.10.1 - Authenticated (Contributor+) PHP Object Injection

2024-04-03 00:00
Francesco Carlucci

Strategic Overview

Status
Patched in 2.11.0
Affected Plugin
CMB2
Affected Version
<= 2.10.1
CVSS
7.5High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2024-1792
View all CMB2 vulnerabilities

At a glance

CVE-2024-1792 is a high-severity Deserialization of Untrusted Data vulnerability in the CMB2 WordPress plugin, affecting versions <= 2.10.1. It carries a CVSS score of 7.5 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 2.11.0; sites on affected versions should update now. Disclosed April 2024, reported by Francesco Carlucci.

Vulnerability Overview

The CMB2 plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 2.10.1 via deserialization of untrusted input from the text_datetime_timestamp_timezone field. This makes it possible for authenticated attackers, with contributor access or higher, to inject a PHP Object. No POP chain is present in the vulnerable plugin. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code. Please note that the plugin is a developer toolkit. For the vulnerability to become exploitable, the presence of a metabox activation in your code (via functions.php for example) is required.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, 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 CMB2 <= 2.10.1 takes an account at Contributor level or above. 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 CMB2 the fix is 2.11.0: builds <= 2.10.1 are affected, anything from 2.11.0 onward is not.

Remediation

Update to version 2.11.0, or a newer patched version

How does WordSec protect against this?

An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: 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: CMB2 2.11.0 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

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