CVE-2020-13382 – CVE-2020-13382 is an incorrect access control v... (How to Fix)

Q: What is the severity of CVE-2020-13382?

CVE-2020-13382 has a CVSS score of 9.1 (CRITICAL). CVE-2020-13382 is an incorrect access control vulnerability in openSIS student information systems that allows unauthenticated attackers to bypass authentication and execute arbitrary PHP code. This affects all openSIS installations through version 7.4, potentially compromising student data, grades, and system integrity.

📋 TL;DR

CVE-2020-13382 is an incorrect access control vulnerability in openSIS student information systems that allows unauthenticated attackers to bypass authentication and execute arbitrary PHP code. This affects all openSIS installations through version 7.4, potentially compromising student data, grades, and system integrity.

💻 Affected Systems

Products:

openSIS

Versions: through 7.4

Operating Systems: Any OS running PHP web server

Default Config Vulnerable: ⚠️ Yes

Notes: All default installations are vulnerable. The vulnerability exists in the core access control mechanisms.

📦 What is this software?

Opensis by Os4ed

View all CVEs affecting Opensis →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise with unauthorized access to all student records, grade manipulation, data exfiltration, and potential ransomware deployment across the entire school district infrastructure.

🟠

Likely Case

Unauthenticated attackers gaining administrative access to modify student records, alter grades, access sensitive personal information, and potentially deploy malware on the server.

🟢

If Mitigated

Limited impact with proper network segmentation and web application firewalls blocking exploitation attempts, though the vulnerability remains present.

🌐 Internet-Facing: HIGH - The vulnerability allows unauthenticated remote exploitation, making internet-facing systems immediate targets for attackers.

🏢 Internal Only: HIGH - Even internally hosted systems are vulnerable to insider threats or compromised internal devices exploiting this weakness.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Public exploit code is available on Packet Storm Security. Attackers can exploit this without any authentication using simple HTTP requests.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Versions after 7.4 (check GitHub commits for specific fixes)

Vendor Advisory: https://github.com/OS4ED/openSIS-Responsive-Design/commits/master

Restart Required: No

Instructions:

1. Update to the latest version from the official GitHub repository. 2. Review and apply relevant security commits from the GitHub history. 3. Test the updated system thoroughly before production deployment.

🔧 Temporary Workarounds

Web Application Firewall Rules

all

Implement WAF rules to block unauthorized access attempts to vulnerable endpoints

# Example ModSecurity rule: SecRule REQUEST_URI "@rx /Modules/.*/index\.php" "id:1001,phase:1,deny,status:403,msg:'openSIS access control bypass attempt'"
# Add similar rules for other vulnerable paths

Network Segmentation

linux

Restrict access to openSIS systems to authorized networks only

# Example iptables rule: iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP

🧯 If You Can't Patch

Immediately take the system offline until patching is possible
Implement strict network access controls allowing only trusted IP addresses to access the openSIS interface

🔍 How to Verify

Check if Vulnerable:

Check if your openSIS version is 7.4 or earlier. Review access logs for unauthorized access attempts to /Modules/*/index.php paths without proper authentication.

Check Version:

Check the version.php file or login page footer. Command: grep -r "version\|Version" /path/to/opensis/ | grep -i "7\.[0-4]\|through 7.4"

Verify Fix Applied:

After updating, attempt to access administrative functions without authentication. Verify that proper authentication is now required for all privileged operations.

📡 Detection & Monitoring

Log Indicators:

Unauthenticated requests to /Modules/*/index.php
Multiple failed login attempts followed by successful administrative access
Unusual PHP file uploads or execution patterns

Network Indicators:

HTTP requests bypassing authentication endpoints
Unusual outbound connections from the openSIS server
Traffic patterns indicating data exfiltration

SIEM Query:

source="web_access.log" AND (uri="/Modules/*/index.php" AND NOT user_agent="*authenticated*") OR (status=200 AND uri="/admin/*" AND src_ip NOT IN [authorized_ips])

📊 Metadata

CVE ID: CVE-2020-13382

CVSS v3 Score: 9.1 (CRITICAL)

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

CWE: CWE-306

Published: July 1, 2020

Last Updated: November 21, 2024

🔗 References

http://packetstormsecurity.com/files/158255/openSIS-7.4-Incorrect-Access-Control.html Exploit,Third Party Advisory,VDB Entry
http://packetstormsecurity.com/files/158331/openSIS-7.4-Unauthenticated-PHP-Code-Execution.html Exploit,Third Party Advisory,VDB Entry
https://github.com/OS4ED/openSIS-Responsive-Design/commits/master Third Party Advisory
http://packetstormsecurity.com/files/158255/openSIS-7.4-Incorrect-Access-Control.html Exploit,Third Party Advisory,VDB Entry
http://packetstormsecurity.com/files/158331/openSIS-7.4-Unauthenticated-PHP-Code-Execution.html Exploit,Third Party Advisory,VDB Entry
https://github.com/OS4ED/openSIS-Responsive-Design/commits/master Third Party Advisory

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