CVE-2020-10562 – This vulnerability in DEVOME GRR before version... (How to Fix)

Q: What is the severity of CVE-2020-10562?

CVE-2020-10562 has a CVSS score of 7.2 (HIGH). This vulnerability in DEVOME GRR before version 3.4.1c allows attackers to upload malicious files through the admin_edit_room.php endpoint due to improper file upload handling. It affects administrators who can access the vulnerable admin interface, potentially leading to remote code execution or system compromise.

📋 TL;DR

This vulnerability in DEVOME GRR before version 3.4.1c allows attackers to upload malicious files through the admin_edit_room.php endpoint due to improper file upload handling. It affects administrators who can access the vulnerable admin interface, potentially leading to remote code execution or system compromise.

💻 Affected Systems

Products:

DEVOME GRR

Versions: All versions before 3.4.1c

Operating Systems: Any OS running PHP web server

Default Config Vulnerable: ⚠️ Yes

Notes: Requires admin access to the GRR application interface.

📦 What is this software?

Grr by Devome

View all CVEs affecting Grr →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system takeover, data exfiltration, or ransomware deployment.

🟠

Likely Case

Unauthorized file upload leading to web shell installation and subsequent server compromise.

🟢

If Mitigated

Limited impact with proper file upload restrictions and web application firewalls in place.

🌐 Internet-Facing: HIGH - The admin interface is typically internet-accessible, making exploitation straightforward.

🏢 Internal Only: MEDIUM - Internal attackers with admin access could exploit this vulnerability.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploitation requires admin credentials but is straightforward once authenticated.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 3.4.1c

Vendor Advisory: https://github.com/JeromeDevome/GRR/releases/tag/v3.4.1c

Restart Required: No

Instructions:

1. Backup current installation. 2. Download GRR v3.4.1c from GitHub releases. 3. Replace vulnerable files with patched version. 4. Verify file upload functionality works correctly.

🔧 Temporary Workarounds

Restrict File Upload Types

all

Implement server-side validation to only allow specific file types (e.g., images) and block executable files.

# Configure web server to block PHP file uploads
# Example Apache: <FilesMatch "\.(php|phtml|phar)$">
#   Deny from all
# </FilesMatch>

Disable admin_edit_room.php

linux

Temporarily disable the vulnerable endpoint until patching can be completed.

# Rename or move the vulnerable file
mv admin_edit_room.php admin_edit_room.php.disabled

🧯 If You Can't Patch

Implement strict file upload validation and sanitization in the application code.
Deploy a web application firewall (WAF) with file upload protection rules.

🔍 How to Verify

Check if Vulnerable:

Check GRR version in admin interface or by examining source files for version markers.

Check Version:

grep -r 'GRR_VERSION' /path/to/grr/installation/ || check admin dashboard

Verify Fix Applied:

Verify version is 3.4.1c or later and test file upload functionality with malicious files.

📡 Detection & Monitoring

Log Indicators:

Unusual file uploads to admin_edit_room.php
POST requests with executable file extensions
Multiple failed upload attempts

Network Indicators:

HTTP POST requests to admin_edit_room.php with file uploads
Unusual outbound connections after file upload

SIEM Query:

source="web_logs" AND uri="/admin_edit_room.php" AND method="POST" AND (file_extension="php" OR file_extension="phtml" OR file_extension="phar")

📊 Metadata

CVE ID: CVE-2020-10562

CVSS v3 Score: 7.2 (HIGH)

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

CWE: CWE-434

Published: March 13, 2020

Last Updated: November 21, 2024

🔗 References

https://github.com/JeromeDevome/GRR/commit/2c6edacd9e15c75a0c2ef472470481ffb6edc7d8 Patch,Third Party Advisory
https://github.com/JeromeDevome/GRR/releases/tag/v3.4.1c Release Notes,Third Party Advisory
https://github.com/skr0x/CVE/tree/master/CVE-2020-10562 Third Party Advisory
https://github.com/JeromeDevome/GRR/commit/2c6edacd9e15c75a0c2ef472470481ffb6edc7d8 Patch,Third Party Advisory
https://github.com/JeromeDevome/GRR/releases/tag/v3.4.1c Release Notes,Third Party Advisory
https://github.com/skr0x/CVE/tree/master/CVE-2020-10562 Third Party Advisory

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