Google Analytics Counter Tracker <= 3.4.1 - Unauthenticated PHP Object Injection

2016-12-11 00:00
Remco Vermeulen

Strategic Overview

Status
Patched in 3.5.0
Affected Version
< 3.5.0
CVSS
9.8Critical
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE pending
View all Google Analytics Counter Tracker vulnerabilities

At a glance

This record tracks a critical-severity Deserialization of Untrusted Data vulnerability in the Google Analytics Counter Tracker WordPress plugin, affecting versions < 3.5.0. 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 3.5.0; sites on affected versions should update now. Disclosed December 2016, reported by Remco Vermeulen.

Vulnerability Overview

The Google Analytics Counter Tracker plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 3.4.1 via deserialization of untrusted input from the vulnerable wpadm_ga_request cookie parameter. 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 Google Analytics Counter Tracker < 3.5.0 takes no account at all. 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 Google Analytics Counter Tracker the fix is 3.5.0: builds < 3.5.0 are affected, anything from 3.5.0 onward is not.

Remediation

Update to version 3.5.0, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: 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: Google Analytics Counter Tracker 3.5.0 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

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