CVE-2020-27976
📋 TL;DR
CVE-2020-27976 is a critical remote command injection vulnerability in osCommerce Phoenix CE that allows attackers to execute arbitrary operating system commands on the server. The vulnerability exists in the admin/mail.php component where the 'from' POST parameter is passed unsanitized to PHP's mail function. This affects all installations running versions before 1.0.5.4.
💻 Affected Systems
- osCommerce Phoenix CE
📦 What is this software?
Oscommerce by Oscommerce
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise allowing attackers to execute arbitrary commands, install backdoors, steal data, pivot to internal networks, and maintain persistent access.
Likely Case
Remote code execution leading to web server compromise, data exfiltration, and potential lateral movement within the network.
If Mitigated
Limited impact if proper input validation and output encoding are implemented, though the vulnerability still presents significant risk.
🎯 Exploit Status
Exploitation requires access to the admin interface but is straightforward once access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.5.4
Vendor Advisory: https://forums.oscommerce.com/topic/459923-oscommerce-phoenix-security-update/
Restart Required: No
Instructions:
1. Backup your current installation. 2. Download version 1.0.5.4 or later from the official osCommerce repository. 3. Replace the affected admin/mail.php file with the patched version. 4. Verify the fix by checking the version number in the admin panel.
🔧 Temporary Workarounds
Disable admin/mail.php access
linuxTemporarily restrict access to the vulnerable component while awaiting patch deployment.
mv admin/mail.php admin/mail.php.disabled
chmod 000 admin/mail.php.disabled
Implement input validation
allAdd input sanitization to the 'from' parameter in admin/mail.php
Edit admin/mail.php and add: $from = filter_var($_POST['from'], FILTER_SANITIZE_EMAIL);
🧯 If You Can't Patch
- Implement strict network segmentation to isolate the osCommerce server from critical systems
- Deploy a web application firewall (WAF) with command injection protection rules
🔍 How to Verify
Check if Vulnerable:
Check if admin/mail.php exists and examine the version number in includes/version.php - if version is less than 1.0.5.4, the system is vulnerable.Check Version:
grep -r 'define.*PROJECT_VERSION' includes/version.phpVerify Fix Applied:
Verify the version number in includes/version.php shows 1.0.5.4 or higher, and check that admin/mail.php has proper input validation for the 'from' parameter.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to admin/mail.php with shell metacharacters in parameters
- Unexpected system command execution from web server process
Network Indicators:
- HTTP requests to admin/mail.php containing shell commands in POST data
- Outbound connections from web server to unexpected destinations
SIEM Query:
source="web_access.log" AND uri="/admin/mail.php" AND (POST_data CONTAINS "|" OR POST_data CONTAINS ";" OR POST_data CONTAINS "`" OR POST_data CONTAINS "$")