CVE-2019-12240

Virim <= 0.4 - PHP Object Injection

2019-05-07 00:00
Magnus K. Stubman

Strategic Overview

Status
Unpatched
Affected Plugin
Virim
Affected Version
<= 0.4
CVSS
9.8Critical
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2019-12240
View all Virim vulnerabilities

At a glance

CVE-2019-12240 is a critical-severity Deserialization of Untrusted Data vulnerability in the Virim WordPress plugin, affecting versions <= 0.4. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed May 2019, reported by Magnus K. Stubman.

Vulnerability Overview

The Virim plugin 0.4 for WordPress allows Insecure Deserialization via s_values, t_values, or c_values in graph.php.

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 Virim <= 0.4 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. No fixed build of this plugin is recorded for Virim yet, so installs running <= 0.4 stay exposed until the vendor ships one.

Remediation

No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.

How does WordSec protect against this?

The attempt arrives as an ordinary request to Virim: 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. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.

  • Firewall
  • Scanner
  • Alerts

External References

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