WordPress WP-Advanced-Search <= 3.3.3 - Remote Code Execution

2020-03-05 00:00
Florian Hauser

Strategic Overview

Status
Patched in 3.3.4
Affected Plugin
WordPress WP-Advanced-Search
Affected Version
< 3.3.4
CVSS
9.8Critical
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE pending
View all WordPress WP-Advanced-Search vulnerabilities

At a glance

This record tracks a critical-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the WordPress WP-Advanced-Search WordPress plugin, affecting versions < 3.3.4. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.3.4; sites on affected versions should update now. Disclosed March 2020, reported by Florian Hauser.

Vulnerability Overview

The WordPress WP-Advanced-Search plugin for WordPress is vulnerable to Remote Code Execution in versions up to, and including, 3.3.3 via the WP_Advanced_Search_Import() function which makes it possible for unauthenticated attackers to execute code on the server through a file upload. This is due to the WP_Advanced_Search_Import() function being hooked via an admin_post_nopriv action that is available to all users.

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 privileges on the target site, 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')

WordPress WP-Advanced-Search < 3.3.4 carries this weakness at WP_Advanced_Search_Import(), and reaching it takes a caller who can reach the endpoint. 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 WordPress WP-Advanced-Search the fix is 3.3.4: builds < 3.3.4 are affected, anything from 3.3.4 onward is not.

Remediation

Update to version 3.3.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to WordPress WP-Advanced-Search: 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: WordPress WP-Advanced-Search 3.3.4 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/8071f117-c341-45bc-8d6e-8aa5d677d65c

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