Gravityforms <= 1.8.19 - Arbitrary File Upload

2015-02-26 00:00

Strategic Overview

Status: Patched in 1.8.20
Affected Plugin: Gravity Forms
Affected Version: < 1.8.20
CVSS: 9.8Critical
Weakness type: CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE: CVE pending

At a glance

This record tracks a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Gravity Forms WordPress plugin, affecting versions < 1.8.20. 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 1.8.20; sites on affected versions should update now. Disclosed February 2015.

Vulnerability Overview

The Gravityforms plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation via the includes/upload.php file in versions up to, and including, 1.8.19. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected sites server which may make remote code execution possible

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-434: Unrestricted Upload of File with Dangerous Type

Reaching this weakness in Gravity Forms < 1.8.20 takes a caller who can reach the endpoint. An unrestricted file upload lets a caller store a file whose type or destination the application does not properly constrain.

If an uploaded file lands anywhere the server will execute, the flaw becomes remote code execution and the site should be treated as fully compromised. For Gravity Forms the fix is 1.8.20: builds < 1.8.20 are affected, anything from 1.8.20 onward is not.

Remediation

Update to version 1.8.20, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Gravity 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: Gravity Forms 1.8.20 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/a6bf60cc-4a07-4d5d-bff3-20d0115a5bd3

Related records

Same weakness class

Other vulnerabilities in Gravity Forms

CVSS Vector

9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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