In recent years, cloud services have become an essential part of many organizations' infrastructure. As such, ensuring secure authentication and authorization have become paramount. CVE-2024-35255 is a newly discovered vulnerability in Azure Identity Libraries and Microsoft Authentication Library that poses a significant risk to organizations relying on these libraries for authentication. This post aims to provide an in-depth understanding of this vulnerability, its potential impact, and possible exploits.
CVE-2024-35255 Vulnerability Details
CVE-2024-35255 is a critical elevation of privilege vulnerability affecting Azure Identity Libraries (for .NET, Java, Python, and JavaScript) and Microsoft Authentication Library (for Android). The flaw can lead to unauthorized users gaining access to sensitive data or even taking control of an organization's Azure environment.
The vulnerability is introduced due to the way the token cache serialization logic is implemented in the Azure Identity Libraries and Microsoft Authentication Library. An attacker with local access to the device running the vulnerable code can potentially read, modify, or tamper with the serialized token cache. This could allow the attacker to escalate their privileges, and potentially impersonate other users and gain access to sensitive resources.
Microsoft has addressed this vulnerability through an update for affected libraries. Organizations using the affected libraries should apply the provided updates as soon as possible to mitigate the risk posed by this flaw.
Exploit Scenario & Code Snippet
As with any vulnerability, understanding the potential risk and exploit scenario is crucial to prioritizing vulnerability management. In the case of CVE-2024-35255, an attacker with local access to a device can exploit this flaw. The attack scenario could involve a malicious insider, a compromised device, or an attacker gaining physical control of a device.
Here's a code snippet demonstrating serialized token cache in Azure Identity Library for Python
from azure.identity import DefaultAzureCredential
from azure.keyvault.secrets import SecretClient
from msal import SerializableTokenCache
cache = SerializableTokenCache()
credential = DefaultAzureCredential(token_cache=cache)
client = SecretClient(vault_url="https://myvault.vault.azure.net";, credential=credential)
secret = client.get_secret("MySecret")
serialized_cache = cache.serialize()
# Attacker can now access the serialized token cache, tamper with it and potentially gain elevated privileges
This code snippet makes use of the DefaultAzureCredential provided by the Azure Identity Library and serializes the token cache using MSAL (Microsoft Authentication Library) SerializableTokenCache.
Original References & Official Patch
Microsoft has acknowledged the vulnerability and released updates for affected libraries. Here are the links to the original advisory and the list of affected libraries, versions, and patches:
- Microsoft Security Advisory: CVE-2024-35255
- Azure Identity Libraries updates
- .NET
- Java
- Python
- JavaScript
- Microsoft Authentication Library (Android) updates: v2.1.
Conclusion
CVE-2024-35255 is a critical elevation of privilege vulnerability that affects Azure Identity Libraries and Microsoft Authentication Library. It's essential for organizations using these libraries to understand the potential impact of this vulnerability and take necessary measures to patch vulnerable installations. By staying informed and proactive in addressing vulnerabilities like CVE-2024-35255, organizations can ensure the continued security of their cloud-based environments, and protect sensitive data and resources from unauthorized access.
Timeline
Published on: 06/11/2024 17:16:03 UTC
Last modified on: 06/14/2024 03:55:56 UTC