CVE-2021-43935 – This vulnerability allows attackers to bypass a... (How to Fix)

Q: What is the severity of CVE-2021-43935?

CVE-2021-43935 has a CVSS score of 8.1 (HIGH). This vulnerability allows attackers to bypass authentication in affected products configured for Single Sign-On (SSO). By manually entering any Active Directory account provisioned in the application without providing a password, attackers gain full access with that account's privileges. Organizations using these products with SSO enabled are affected.

📋 TL;DR

This vulnerability allows attackers to bypass authentication in affected products configured for Single Sign-On (SSO). By manually entering any Active Directory account provisioned in the application without providing a password, attackers gain full access with that account's privileges. Organizations using these products with SSO enabled are affected.

💻 Affected Systems

Products:

Rockwell Automation FactoryTalk View SE

Versions: All versions prior to v11.0

Operating Systems: Windows

Default Config Vulnerable: ✅ No

Notes: Only affects systems configured to use SSO authentication. Systems using other authentication methods are not vulnerable.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete compromise of the application by any attacker who can reach it, leading to data theft, system takeover, and lateral movement within the network.

🟠

Likely Case

Unauthorized access to sensitive application data and functionality by internal or external attackers who discover the vulnerability.

🟢

If Mitigated

Limited impact if SSO is disabled or proper network segmentation prevents access to vulnerable systems.

🌐 Internet-Facing: HIGH - If the application is exposed to the internet, attackers can easily exploit this without authentication.

🏢 Internal Only: HIGH - Even internally, any user with network access could exploit this to gain elevated privileges.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires no special tools or knowledge - just manual entry of AD account names in the application interface.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: FactoryTalk View SE v11.0

Vendor Advisory: https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1657.html

Restart Required: Yes

Instructions:

1. Download FactoryTalk View SE v11.0 from Rockwell Automation. 2. Backup current configuration. 3. Install the update following vendor documentation. 4. Restart the system.

🔧 Temporary Workarounds

Disable SSO Authentication

windows

Switch to alternative authentication methods until patching is possible

Configure application to use local authentication or other non-SSO methods per vendor documentation

Network Segmentation

all

Restrict access to vulnerable systems to only trusted networks

Configure firewall rules to limit access to FactoryTalk View SE systems

🧯 If You Can't Patch

Implement strict network access controls to limit who can reach the vulnerable systems
Monitor authentication logs for unusual AD account usage patterns

🔍 How to Verify

Check if Vulnerable:

Check if FactoryTalk View SE is configured for SSO authentication and version is below v11.0

Check Version:

Check version in FactoryTalk View SE application interface or installation directory

Verify Fix Applied:

Confirm version is v11.0 or later and test that SSO authentication now requires proper credentials

📡 Detection & Monitoring

Log Indicators:

Authentication logs showing successful logins without password verification
Multiple failed authentication attempts followed by successful SSO login

Network Indicators:

Unusual authentication traffic patterns to FactoryTalk View SE systems

SIEM Query:

source="FactoryTalk" AND event_type="authentication" AND result="success" AND auth_method="SSO" AND NOT password_required="true"

📊 Metadata

CVE ID: CVE-2021-43935

CVSS v3 Score: 8.1 (HIGH)

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

CWE: CWE-288

Published: December 15, 2021

Last Updated: November 21, 2024

🔗 References

https://www.cisa.gov/uscert/ics/advisories/icsma-21-343-01 Mitigation,Third Party Advisory,US Government Resource
https://www.cisa.gov/uscert/ics/advisories/icsma-21-343-01 Mitigation,Third Party Advisory,US Government Resource

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🔗 Related Vulnerabilities

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