CVE-2022-3861

Betheme <= 26.5.1.4 - Authenticated (Subscriber+) PHP Object Injection

2022-11-18 00:00
Julien Ahrens

Strategic Overview

Status
Patched in 26.6
Affected Theme
Betheme
Affected Version
<= 26.5.1.4
CVSS
8.8High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2022-3861
View all Betheme vulnerabilities

At a glance

CVE-2022-3861 is a high-severity Deserialization of Untrusted Data vulnerability in the Betheme WordPress theme, affecting versions <= 26.5.1.4. 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 at Subscriber level or above. The issue is fixed in version 26.6; sites on affected versions should update now. Disclosed November 2022, reported by Julien Ahrens.

Vulnerability Overview

The Betheme theme for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 26.5.1.4 via deserialization of untrusted input supplied via the import, mfn-items-import-page, and mfn-items-import parameters passed through the mfn_builder_import, mfn_builder_import_page, importdata, importsinglepage, and importfromclipboard functions. This makes it possible for authenticated attackers, with subscriber level permissions and above to inject a PHP Object. The additional presence of a POP chain would make it possible for attackers to execute code, retrieve sensitive data, delete files, etc..

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 Betheme <= 26.5.1.4 takes an account at Subscriber 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 Betheme the fix is 26.6: builds <= 26.5.1.4 are affected, anything from 26.6 onward is not.

Remediation

Update to version 26.6, or a newer patched version

How does WordSec protect against this?

An attacker needs Subscriber 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: Betheme 26.6 closes this, and updating the theme is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2022-3861https://www.wordfence.com/threat-intel/vulnerabilities/id/f5e984d5-2537-4a4a-a071-084e0c1c3b5ehttps://nvd.nist.gov/vuln/detail/CVE-2022-3861

Related records

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