CVE-2021-24307

All in One SEO <= 4.1.0.1 - Authenticated Code Injection

2021-05-09 00:00
Vincent MICHEL

Strategic Overview

Status
Patched in 4.1.0.2
Affected Plugin
All in One SEO – AI SEO Plugin to Boost SEO Rankings & Traffic (Schema, Local SEO, Sitemap & SEO Insights)
Affected Version
< 4.1.0.2
CVSS
8.8High
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE-2021-24307
View all All in One SEO – AI SEO Plugin to Boost SEO Rankings & Traffic (Schema, Local SEO, Sitemap & SEO Insights) vulnerabilities

At a glance

CVE-2021-24307 is a high-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the All in One SEO WordPress plugin, affecting versions < 4.1.0.2. 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 4.1.0.2; sites on affected versions should update now. Disclosed May 2021, reported by Vincent MICHEL.

Vulnerability Overview

The All in One SEO – Best WordPress SEO Plugin – Easily Improve Your SEO Rankings before 4.1.0.2 enables authenticated users with "aioseo_tools_settings" privilege (most of the time admin) to execute arbitrary code on the underlying host. Users can restore plugin's configuration by uploading a backup .ini file in the section "Tool > Import/Export". However, the plugin attempts to unserialize values of the .ini file. Moreover, the plugin embeds Monolog library which can be used to craft a gadget chain and thus trigger system command execution.

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')

All in One SEO < 4.1.0.2 carries this weakness at aioseo_tools_settings, and reaching it takes any authenticated account. 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 All in One SEO the fix is 4.1.0.2: builds < 4.1.0.2 are affected, anything from 4.1.0.2 onward is not.

Remediation

Update to version 4.1.0.2, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to All in One SEO: 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: All in One SEO 4.1.0.2 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24307https://www.wordfence.com/threat-intel/vulnerabilities/id/b2a98c69-5f76-41f4-8a12-0523285647fbhttps://nvd.nist.gov/vuln/detail/CVE-2021-24307

Related records

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