Leveraging NetScaler to Mitigate ConnectWise ScreenConnect Authentication Bypass vulnerability (CVE-2024-1709)

Proactive actions are crucial in today's digital landscape to successfully combat evolving cyber threats. One such threat, CVE-2024-1709, has recently surfaced, targeting ConnectWise ScreenConnect versions 23.9.7 and earlier. This vulnerability poses a significant risk, potentially allowing attackers to bypass authentication using an alternate path or channel vulnerability.

The Exploit
Due to a particular .NET feature that processes additional URL path components beyond the legitimate one, attackers are able to bypass access restrictions and manipulate the setup wizard file on ScreenConnect instances that are already configured. This allowed them to grant elevated privileges or full administrator controls thus rewriting the existing user access database. Once they gain admin rights, attackers can upload malicious files or execute arbitrary codes on the system.

In this blog post, we'll focus on how organizations can utilize NetScaler Web Application Firewall (WAF) signatures to effectively mitigate the risks associated with CVE-2024-1709.

Leveraging Signature-based Protections

NetScaler WAF provides a robust defense mechanism against CVE-2024-1709 and similar vulnerabilities through its extensive database of signatures. These signatures are meticulously crafted to identify and block known attack patterns associated with CVE-2024-1709, enabling organizations to fortify their defenses against emerging threats.

Comprehensive Threat Intelligence: 

NetScaler WAF continuously updates its signature database with the latest threat intelligence feeds, ensuring organizations stay ahead of evolving cyber threats, including CVE-2024-1709. By leveraging up-to-date threat intelligence, NetScaler WAF can effectively detect and mitigate emerging vulnerabilities, enhancing overall security posture.

From Unified Security Console:

1. Navigate to the Unified security flow - From your NetScaler Console Service, navigate to Security > Security Dashboard
2. Select your application from the ‘Unsecured Applications’ tab. If you’ve previously configured using the Unified Security flow, you’ll find your application under the ‘Secured Application’ tab and click on the edit icon.
3. Select the ‘CVE Protections’ tile - 
   
4. Search for the CVE from the list of signatures and enable the same - 
   

From NetScaler ADC, ensure you’re running signature version 125 and -

1. Search your signatures for ‘CVE-2024-1709’ LogString.
2. Select the results.
3. Choose “Enable Rules” and click OK.
   

Real-time Detection and Mitigation: 

NetScaler WAF's signature-based protections operate in real-time, enabling organizations to swiftly detect and mitigate unauthorized access attempts associated with CVE-2024-1709. By analyzing web traffic against its signature database, NetScaler WAF can identify and block malicious activities before they compromise sensitive information or critical systems.

Customization and Flexibility:

NetScaler WAF allows organizations to customize signature-based protections based on their specific security requirements and risk profile. By tailoring signature-based rules and policies to their environment, organizations can effectively mitigate CVE-2024-1709 and other vulnerabilities while minimizing false positives and disruptions to legitimate traffic.

CVE-2024-1709 highlights the importance of proactive cybersecurity measures in safeguarding organizational assets against emerging cyber threats. By leveraging NetScaler WAF signatures, organizations can effectively mitigate the risks associated with CVE-2024-1709 and enhance their overall security posture. With comprehensive threat intelligence, real-time detection, and customization capabilities, NetScaler WAF empowers organizations to defend against evolving cyber threats and protect their critical assets with confidence.