Understanding CVE-2024-56337: A Critical Apache Tomcat Vulnerability

In today’s ever-evolving cybersecurity landscape, the recent discovery of CVE-2024-56337 has put a spotlight on the need for robust and proactive security measures. This critical vulnerability, affecting Apache Tomcat versions 11.0.0-M1 through 11.0.1, 10.1.0-M1 through 10.1.33, and 9.0.0.M1 through 9.0.97, underscores the importance of timely updates and secure configurations. Here, we delve into the details of this vulnerability and the steps needed to mitigate it.

What is CVE-2024-56337?

CVE-2024-56337 is a Time-of-check Time-of-use (TOCTOU) race condition vulnerability that arises from an incomplete mitigation of a prior issue, CVE-2024-50379. This flaw can potentially enable remote code execution (RCE) on systems with specific configurations, posing a significant risk to affected deployments.

Who is Affected?

The vulnerability impacts:

1. Apache Tomcat Versions:

   • 11.0.0-M1 through 11.0.1

   • 10.1.0-M1 through 10.1.33

   • 9.0.0.M1 through 9.0.97

2. Operating Systems:

   • Case-insensitive file systems (e.g., Windows and macOS).

3. Tomcat Configuration:

   • Systems where the default servlet’s write capabilities are enabled (i.e., the

     readonly

     initialization parameter is set to

     false

     ).

Security Implications

Exploiting CVE-2024-56337 could allow attackers to execute arbitrary code on the affected system. This can lead to system compromise, data breaches, and other severe security incidents.

Mitigation Steps

1. Upgrade Apache Tomcat

Ensure you are running a secure version of Apache Tomcat:

• For Tomcat 11: Update to version 11.0.2 or later.

• For Tomcat 10.1: Update to version 10.1.34 or later.

• For Tomcat 9.0: Update to version 9.0.98 or later.

2. Configure Java System Properties

Proper configuration of Java system properties is essential:

• Java 8 or Java 11: Set the system property

  sun.io.useCanonCaches

  to

  false

  (default is

  true

  ).

• Java 17: Ensure

  sun.io.useCanonCaches

  is set to

  false

  (default is

  false

  ).

• Java 21 and later: No additional configuration is required as the associated cache has been removed.

3. Review Tomcat Configurations

If the default servlet’s write capabilities are enabled, ensure they are necessary for your use case. Disable write capabilities where possible by setting the

readonly

true

Recommendations

To protect your systems from CVE-2024-56337:

1. Apply Updates Promptly: Updating to the latest versions of Apache Tomcat is the most effective mitigation.

2. Verify System Configurations: Review and secure your Tomcat configurations to prevent unnecessary exposure.

3. Monitor Official Channels: Stay informed through Apache Tomcat’s official advisories and announcements for further updates or guidance.

Conclusion

CVE-2024-56337 highlights the critical importance of staying vigilant in maintaining and securing software deployments. By promptly addressing this vulnerability through updates and configuration adjustments, organizations can safeguard their systems against potential exploitation. For more details and official updates, visit the Apache Tomcat advisory page.

Stay safe, stay updated, and ensure that your systems are secure against evolving threats.