CVE-2023-1549

Ad Inserter <= 2.7.25 - Authenticated (Admin+) PHP Object Injection

2023-04-19 00:00
Nguyen Huu Do

Strategic Overview

Status
Patched in 2.7.26
Affected Version
<= 2.7.25
CVSS
7.2High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2023-1549
View all Ad Inserter – Ad Manager & AdSense Ads vulnerabilities

At a glance

CVE-2023-1549 is a high-severity Deserialization of Untrusted Data vulnerability in the Ad Inserter WordPress plugin, affecting versions <= 2.7.25. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Admin level or above. The issue is fixed in version 2.7.26; sites on affected versions should update now. Disclosed April 2023, reported by Nguyen Huu Do.

Vulnerability Overview

The Ad Inserter plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.7.25 via deserialization of untrusted input from the $exported_settings variable when importing settings. This allows authenticated attackers, with administrative privileges, 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.

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 Ad Inserter <= 2.7.25 takes an account at Admin 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 Ad Inserter the fix is 2.7.26: builds <= 2.7.25 are affected, anything from 2.7.26 onward is not.

Remediation

Update to version 2.7.26, or a newer patched version

How does WordSec protect against this?

An attacker needs Admin 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: Ad Inserter 2.7.26 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

Related records

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