WP Fastest Cache <= 0.8.5.9 - Local File Inclusion

2016-07-13 00:00
Yorick Koster,

Strategic Overview

Status
Patched in 0.8.6.0
Affected Plugin
WP Fastest Cache – WordPress Cache Plugin
Affected Version
<= 0.8.5.9
CVSS
8.8High
Weakness type
CWE-98 · Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
CVE
CVE pending
View all WP Fastest Cache – WordPress Cache Plugin vulnerabilities

At a glance

This record tracks a high-severity Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion') vulnerability in the WP Fastest Cache WordPress plugin, affecting versions <= 0.8.5.9. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). The issue is fixed in version 0.8.6.0; sites on affected versions should update now. Disclosed July 2016, reported by Yorick Koster,.

Vulnerability Overview

The WP Fastest Cache plugin for WordPress is vulnerable to Local File Inclusion in versions up to, and including, 0.8.5.9 via the id POST parameter. This allows authenticated attackers to include and execute arbitrary files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution in cases where images and other “safe” file types can be uploaded and included. This is due to an impartial fix of https://ti.wordfence.io/vulnerabilities/3ebe25a7-fa4d-4e3f-b969-2ff3a8388b06.

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-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')

WP Fastest Cache <= 0.8.5.9 carries this weakness at safe, and reaching it takes a caller who can reach the endpoint. PHP file inclusion means a path used by include or require is built from request data, so the file that gets executed is under the caller's influence.

Including an attacker-influenced file executes its contents, which is why this class is routinely chained with an upload or log-poisoning step to reach code execution. For WP Fastest Cache the fix is 0.8.6.0: builds <= 0.8.5.9 are affected, anything from 0.8.6.0 onward is not.

Remediation

Update to version 0.8.6.0, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to WP Fastest 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: WP Fastest Cache 0.8.6.0 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/e8fe4aa7-13e6-48ec-afec-2888edd999f5

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