CVE-2023-38889 has been assigned for a critical vulnerability affecting the Alluxio framework, specifically for versions v.2.9.3 and earlier. This issue has a high-level impact because it allows attackers to execute arbitrary code by crafting malicious scripts targeting the Alluxio's username parameter. In this post, we'll discuss the issue in detail, provide an overview of the affected component, share a code snippet to help illustrate the exploit, and outline crucial steps in remediation.

Vulnerability Details

The vulnerability centers around a flaw in the Alluxio.util.CommonUtils.getUnixGroups(java.lang.String) function when processing the username's parameter. Attackers can exploit this by crafting a malicious script that, when executed, grants them unauthorized access to sensitive data and the potential for more harmful actions within the target system.

Affected Component

The affected component within Alluxio's framework is Alluxio.util.CommonUtils.getUnixGroups(java.lang.String), responsible for getting Unix group information for the specified user.

Code Snippet Illustrating the Vulnerability

Here's an example code snippet that demonstrates how a malicious script can exploit the vulnerability:

public static List<String> getUnixGroups(String username) throws IOException {
  if (username == null) {
    return Collections.emptyList();
  String command = String.format("id -Gn '%s'", username);
  Process process = Runtime.getRuntime().exec(command);
  BufferedReader reader = new BufferedReader(
      new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_8));

In this example, the username parameter is improperly checked, resulting in the possibility of arbitrary code execution through a carefully crafted input.

Relevant Original References

1. CVE-2023-38889 - Alluxio Project Vulnerability
2. Alluxio Util Javadoc

Exploit Details

The following steps provide an overview of how an attacker could exploit the CVE-2023-38889 vulnerability:

1. Craft a malicious script that takes advantage of the unchecked username parameter in the getUnixGroups() function.

Inject the malicious script into the target system.

3. Execute the script within the target system, causing the arbitrary code to be executed with the privileges of the Alluxio service.

What You Can Do to Mitigate the Risk

To minimize the impact of this vulnerability and properly safeguard your Alluxio environment, follow these steps:

1. Update your Alluxio deployment to the latest stable version available (v2.9.4 or newer) as soon as possible. Patches addressing the issue are available on Alluxio's official GitHub repository:

Regularly scrutinize and sanitize user inputs, particularly those concerning username parameters.

3. Restrict access to sensitive functions like the getUnixGroups(), ensuring only authorized personnel can access them.
4. Invest in implementing proper monitoring and logging solutions to help detect any unusual activities within your environment.


CVE-2023-38889 is a severe vulnerability that affects Alluxio.BufferSlayer versions up to v.2.9.3, and it allows unauthorized access and arbitrary code execution if successfully exploited. This long-read has shed light on the issue, provided a code snippet for better understanding, and detailed steps to mitigate the risks. Be vigilant in maintaining a secure Alluxio deployment to avoid falling victim to this vulnerability.


Published on: 08/15/2023 17:15:00 UTC
Last modified on: 08/25/2023 12:58:00 UTC