The cybersecurity firm Wiz, led by former Microsoft employees, found an “unprecedented critical vulnerability” in Microsoft’s Azure cloud platform and notified Microsoft earlier in August. Microsoft paid the firm a bounty for the discovery and fixing the problem.
ChaosDB in Azure cloud platform
The tech company said that there is no indication that external entities outside the researcher had access to the primary read-write key associated with users’ Azure Cosmos DB account(s). In addition, they are not aware of any data access because of this vulnerability. Microsoft stated,
“Microsoft has recently become aware of a vulnerability in Azure Cosmos DB that could potentially allow a user to gain access to another customer’s resources by using the account’s primary read-write key. This vulnerability was reported to us in confidence by an external security researcher. Once we became aware of this issue on Aug 12, 2021, we mitigated the vulnerability immediately,”
Wiz published a blog post titled “Critical Vulnerability in Microsoft Azure Cosmos DB”. They gave details about ChaosDB, saying,
“#ChaosDB is an unprecedented critical vulnerability in the Azure cloud platform that allows for remote account takeover of Azure’s flagship database – Cosmos DB. The vulnerability disclosed to Microsoft in August 2021 by Wiz Research Team gives any Azure user full admin access (read, write, delete) to another customer’s Cosmos DB instances without authorization. The vulnerability has a trivial exploit that doesn’t require any previous access to the target environment and impacts thousands of organizations, including numerous Fortune 500 companies.”
Through a chain of vulnerabilities in the Jupyter Notebook feature of Cosmos DB, a malicious actor can query information about the target Cosmos DB Jupyter Notebook. Then, the attacker will reach a set of credentials related to the target Cosmos DB account, the Jupyter Notebook compute, and the Jupyter Notebook Storage account, including the Primary Key.
These credentials enable hackers to view, modify, and delete data in the target Cosmos DB account via multiple channels. Below is a diagram that illustrates the attack. To mitigate the risk, Microsoft advises customers to regenerate the Cosmos DB Primary Keys. On Aug 26, 2021, Microsoft notified over 30% of Cosmos DB customers about the potential security breach.