Ad Inserter < 2.7.11 - Authenticated (Admin+) Remote Code Execution

2022-02-03 00:00
Viktor Markopoulos

Strategic Overview

Status
Patched in 2.7.11
Affected Plugin
Ad Inserter – Ad Manager & AdSense Ads
Affected Version
< 2.7.11
CVSS
7.2High
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE pending
View all Ad Inserter – Ad Manager & AdSense Ads vulnerabilities

At a glance

This record tracks a high-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the Ad Inserter WordPress plugin, affecting versions < 2.7.11. 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 2.7.11; sites on affected versions should update now. Disclosed February 2022, reported by Viktor Markopoulos.

Vulnerability Overview

The Ad Inserter plugin for WordPress is vulnerable to Remote Code Execution in versions before 2.7.11 via the settings.php file. This allows authenticated attackers with admin-level privileges to execute code on the server as well as perform stored cross-site scripting attacks.

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-94: Improper Control of Generation of Code ('Code Injection')

Reaching this weakness in Ad Inserter < 2.7.11 takes an account at Admin level or above. Code injection means input from a request reaches a language construct that evaluates code, so the attacker's text is executed rather than treated as data.

The injected code runs with the web server's privileges, giving the attacker the same access to the database and filesystem as WordPress itself. For Ad Inserter the fix is 2.7.11: builds < 2.7.11 are affected, anything from 2.7.11 onward is not.

Remediation

Update to version 2.7.11, 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 2.7.11 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/a596c9c4-ceb4-470c-8ad5-986cd62da91e

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