Ninja Forms Contact Form – The Drag and Drop Form Builder for WordPress <= 3.6.10 - Code Injection

2022-06-15 00:00
Anonymous

Strategic Overview

Status
Patched in 3.0.34.2
Affected Plugin
Ninja Forms – The Contact Form Builder That Grows With You
Affected Version
3.0.34.1 – 3.6.10 · 7 branches
CVSS
9.8Critical
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE pending
View all Ninja Forms – The Contact Form Builder That Grows With You vulnerabilities

At a glance

This record tracks a critical-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the Ninja Forms WordPress plugin, affecting versions 3.0.34.1 – 3.6.10 · 7 branches. 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 3.0.34.2; sites on affected versions should update now. Disclosed June 2022.

Vulnerability Overview

The Ninja Forms Contact Form – The Drag and Drop Form Builder for WordPress plugin for WordPress is vulnerable to code injection in versions up to, and including 3.6.10 due to insufficient validation on Merge Tags that makes it possible to call arbitrary Ninja Form classes. This could lead to a variety of actions, however, one notable one is deserialization when the NF_Admin_Processes_ImportForm::startup method is called. On sites with a POP chain this could be used to achieve remote code execution in the worst possible scenarios.

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-94: Improper Control of Generation of Code ('Code Injection')

Reaching this weakness in Ninja Forms 3.0.34.1 – 3.6.10 · 7 branches 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 Ninja Forms the fix is 3.0.34.2: builds 3.0.34.1 – 3.6.10 · 7 branches are affected, anything from 3.0.34.2 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 3.0.34.2, 3.1.10, 3.2.28, 3.3.21.4, 3.4.34.2, 3.5.8.4, 3.6.11

How does WordSec protect against this?

The attempt arrives as an ordinary request to Ninja Forms: 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: Ninja Forms 3.0.34.2 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/df46b3d5-a433-47b5-99b8-117591f7dd16

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