CVE-2023-37918: Dapr API Token Authentication Bypass Vulnerability and Its Fixes

Dapr (Distributed Application Runtime) is an open-source, event-driven, portable runtime system that simplifies the development of distributed applications across cloud and edge environments. A critical vulnerability has been discovered in Dapr which allows an attacker to bypass the API token authentication mechanism. In this article, we'll discuss the details of this vulnerability, along with code snippets, references, and possible fixes.

Vulnerability Details

The vulnerability, assigned with the identifier CVE-2023-37918, affects Dapr users who have configured API token authentication. API tokens are essentially secrets that allow services in the Dapr system to communicate securely with each other. They are used by the Dapr sidecar, a lightweight process that runs alongside the user's application to handle communication, to authenticate incoming calls from the application. However, an attacker can craft a specific HTTP request that the Dapr sidecar always allows, even if the supplied dapr-api-token value is invalid or missing.

Exploit Details

While the exact details of the exploit aren't disclosed, it likely involves sending a carefully crafted HTTP request to the target Dapr sidecar with an invalid or missing dapr-api-token header value. Due to the vulnerability, the Dapr sidecar might not validate the token correctly and allow the request to be processed.

Here is a sample code snippet showing how an attacker might create an HTTP request

import requests

headers = {
  "Content-Type": "application/json",
  "dapr-api-token": "INVALID_OR_MISSING_API_TOKEN"
}
url = "http://TARGET_DAPR_SIDECAR_HOST:350/v1./invoke/SOME_METHOD";

response = requests.post(url, headers=headers, data={})

print(response.status_code)
print(response.text)

If the request is successful, it would imply that token authentication has been bypassed and the attacker could gain unauthorized access to the Dapr system.

Fixes and Recommendations

To fix this vulnerability, users are encouraged to upgrade their Dapr installations to version 1.10.9 or 1.11.2. These versions contain patches that resolve the issue, preventing attackers from bypassing API token authentication.

Follow the official documentation for installation and upgrading instructions

1. Dapr v1.10.9: https://github.com/dapr/dapr/releases/tag/v1.10.9
2. Dapr v1.11.2: https://github.com/dapr/dapr/releases/tag/v1.11.2

At the time of writing, there are no known workarounds for this vulnerability, so it is highly recommended that users upgrade to one of the above-mentioned fixed versions.

Conclusion

The discovery of the CVE-2023-37918 vulnerability in Dapr highlights the importance of continuous security testing and staying up to date with the latest patches and updates. By upgrading Dapr to version 1.10.9 or 1.11.2, users can mitigate the risk of unauthorized access and protect their distributed applications from potential attacks. Be proactive about your application security, and keep an eye on future security announcements to ensure the safety and integrity of your systems.

Timeline

Published on: 07/21/2023 21:15:00 UTC
Last modified on: 07/31/2023 17:30:00 UTC