CVE-2015-4455 – This vulnerability allows remote attackers to u... (How to Fix)

Q: What is the severity of CVE-2015-4455?

CVE-2015-4455 has a CVSS score of 9.8 (CRITICAL). This vulnerability allows remote attackers to upload arbitrary files with executable extensions to WordPress sites using the Aviary Image Editor Add-on For Gravity Forms plugin. Attackers can then execute malicious code by directly accessing uploaded files, potentially leading to complete system compromise. Affected systems are WordPress installations with the vulnerable plugin version.

📋 TL;DR

This vulnerability allows remote attackers to upload arbitrary files with executable extensions to WordPress sites using the Aviary Image Editor Add-on For Gravity Forms plugin. Attackers can then execute malicious code by directly accessing uploaded files, potentially leading to complete system compromise. Affected systems are WordPress installations with the vulnerable plugin version.

💻 Affected Systems

Products:

WordPress Aviary Image Editor Add-on For Gravity Forms

Versions: 3.0 beta

Operating Systems: All

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects WordPress installations with this specific plugin version.

📦 What is this software?

Aviary Image Editor Add On For Gravity Forms by Aviary Image Editor Add On For Gravity Forms Project

View all CVEs affecting Aviary Image Editor Add On For Gravity Forms →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete server takeover with remote code execution, data theft, defacement, and lateral movement to other systems.

🟠

Likely Case

Webshell installation leading to data exfiltration, site defacement, or use as part of a botnet.

🟢

If Mitigated

File uploads blocked or sanitized, preventing execution of malicious payloads.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Simple file upload exploit with publicly available proof-of-concept code.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Versions after 3.0 beta

Vendor Advisory: https://wordpress.org/plugins/aviary-image-editor-add-on-for-gravity-forms/

Restart Required: No

Instructions:

1. Update to latest version of Aviary Image Editor Add-on For Gravity Forms plugin. 2. Remove any existing vulnerable version. 3. Verify no malicious files remain in wp-content/uploads/gform_aviary directory.

🔧 Temporary Workarounds

Disable plugin

linux

Temporarily disable the vulnerable plugin until patched

mv /path/to/wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms /path/to/wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms.disabled

Restrict upload directory access

linux

Block direct access to the vulnerable upload directory

echo 'Deny from all' > /path/to/wp-content/uploads/gform_aviary/.htaccess

🧯 If You Can't Patch

Implement web application firewall rules to block file uploads with executable extensions
Regularly monitor and clean wp-content/uploads/gform_aviary directory for suspicious files

🔍 How to Verify

Check if Vulnerable:

Check WordPress plugin version in admin panel or examine /wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms/readme.txt

Check Version:

grep -i 'version' /path/to/wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms/readme.txt

Verify Fix Applied:

Confirm plugin version is updated and test file upload functionality with executable extensions

📡 Detection & Monitoring

Log Indicators:

Unusual file uploads to /wp-content/uploads/gform_aviary/
HTTP requests to executable files in upload directory
POST requests to includes/upload.php

Network Indicators:

File uploads with .php, .exe, .sh extensions to WordPress site
Subsequent requests to uploaded executable files

SIEM Query:

source="web_logs" AND (uri="/wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms/includes/upload.php" OR uri CONTAINS "/wp-content/uploads/gform_aviary/")

📊 Metadata

CVE ID: CVE-2015-4455

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-434

Published: May 23, 2017

Last Updated: April 20, 2025

🔗 References

http://packetstormsecurity.com/files/132256/WordPress-Aviary-Image-Editor-Add-On-For-Gravity-Forms-3.0-Beta-Shell-Upload.html Exploit,Third Party Advisory
http://www.vapid.dhs.org/advisory.php?v=125 Exploit,Third Party Advisory
http://packetstormsecurity.com/files/132256/WordPress-Aviary-Image-Editor-Add-On-For-Gravity-Forms-3.0-Beta-Shell-Upload.html Exploit,Third Party Advisory
http://www.vapid.dhs.org/advisory.php?v=125 Exploit,Third Party Advisory

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