W3 Total Cache <= 0.9.4.1 - Arbitrary Code Execution via settings import

2016-09-26 00:00
SecuPress

Strategic Overview

Status
Patched in 0.9.5
Affected Plugin
W3 Total Cache
Affected Version
<= 0.9.4.1
CVSS
7.2High
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE pending
View all W3 Total Cache vulnerabilities

At a glance

This record tracks a high-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the W3 Total Cache WordPress plugin, affecting versions <= 0.9.4.1. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). The issue is fixed in version 0.9.5; sites on affected versions should update now. Disclosed September 2016, reported by SecuPress.

Vulnerability Overview

The W3 Total Cache plugin for WordPress is vulnerable to Authenticated Arbitrary Code Execution via settings import in versions up to, and including, 0.9.4.1. This makes it possible for authenticated attackers to inject and execute arbitrary 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-94: Improper Control of Generation of Code ('Code Injection')

Reaching this weakness in W3 Total Cache <= 0.9.4.1 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 W3 Total Cache the fix is 0.9.5: builds <= 0.9.4.1 are affected, anything from 0.9.5 onward is not.

Remediation

Update to version 0.9.5, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to W3 Total Cache: 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: W3 Total Cache 0.9.5 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/eb367998-5c5c-4c4d-81cb-519023f028e6

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