Easy Digital Downloads <= 2.5.7 - PHP Object Injection

2016-03-02 00:00
Danny van Kooten

Strategic Overview

Status
Patched in 2.5.8
Affected Plugin
Easy Digital Downloads – eCommerce Payments and Subscriptions made easy
Affected Version
<= 2.5.7
CVSS
9.8Critical
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE pending
View all Easy Digital Downloads – eCommerce Payments and Subscriptions made easy vulnerabilities

At a glance

This record tracks a critical-severity Deserialization of Untrusted Data vulnerability in the Easy Digital Downloads WordPress plugin, affecting versions <= 2.5.7. 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 2.5.8; sites on affected versions should update now. Disclosed March 2016, reported by Danny van Kooten.

Vulnerability Overview

The Easy Digital Downloads plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.5.7 via deserialization of untrusted input from cookies and request parameters. This allows unauthenticated attackers to inject a PHP Object.

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-502: Deserialization of Untrusted Data

Reaching this weakness in Easy Digital Downloads <= 2.5.7 takes a caller who can reach the endpoint. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For Easy Digital Downloads the fix is 2.5.8: builds <= 2.5.7 are affected, anything from 2.5.8 onward is not.

Remediation

Update to version 2.5.8, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Easy Digital Downloads: 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: Easy Digital Downloads 2.5.8 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/b4cd5c42-bba2-4900-b450-a575c0007402

Related records

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