Microsoft Azure Synapse Pwnalytics

Since March 10, Tenable Research has attempted to work with Microsoft to address two serious flaws in the underlying infrastructure of Azure Synapse Analytics.

Synapse Analytics is a platform used for machine learning, data aggregation and other computational work. The service is currently listed under the high-impact scenarios in Microsoft’s Azure Bug Bounty program. Microsoft states that products and scenarios listed under that heading have “the highest potential impact to customer security.”

Tenable Research has discovered two serious flaws in the underlying infrastructure that this service runs on. These flaws allow a user to escalate privileges to that of the root user within the underlying Apache Spark virtual machines, or to poison the hosts file of all nodes in an Apache Spark pool. The keys, secrets and services accessible via these vulnerabilities have traditionally allowed further lateral movement and compromise of Microsoft-owned infrastructure, which could potentially lead to a compromise of other customers’ data as we’ve seen in several other cases recently, such as Wiz’s ChaosDB and Orca’s SynLapse. Microsoft has made the claim, however, that cross-tenant access is not possible via these attack vectors.

Tenable reported these issues to Microsoft on March 10, 2022. Microsoft began rolling out a fix for the privilege escalation issue as early as April 30, 2022. At this time, Tenable believes that the fix has been successfully rolled out to all regions. No action is needed from end users in order to ensure their environments are no longer affected. The hosts file poisoning attack remains unpatched at the time of this writing. Due to the nature of these vulnerabilities and the disclosure process, we do not have CVE reference numbers for them.

See our post on the Tenable TechBlog for more detailed information regarding our interactions with Microsoft and the technical details of these flaws.

During the disclosure process, Microsoft representatives initially seemed to agree that these were critical issues. Microsoft developed and implemented a patch for the privilege escalation without further information from Tenable Research. During the final days of the disclosure process, Microsoft Security Response Center (MSRC) began attempting to downplay the severity of the privilege escalation issue and classified it as a “best practice recommendation,” rather than a security issue. Despite clear evidence to the contrary, MSRC declined a bounty or acknowledgement for this finding. After being notified of our intent to publish information about the vulnerabilities, Microsoft representatives reversed the prior decision, classifying these issues as security-related, demonstrating a clear lack of communication among the teams involved within Microsoft.

These flaws and our researchers’ interactions with Microsoft demonstrate the difficulties involved in addressing security-related issues in cloud environments. The entire process is largely out of customer control. Customers are entirely beholden to the cloud providers to fix reported issues. The good news, though, is that once an issue is fixed, it’s fixed. Customers generally don’t have any actions to take since everything happens behind the scenes. The bad news, however, is that the cloud providers rarely give notice that a security-related flaw was ever present in the first place.

For more detailed information regarding our interactions with Microsoft and the technical details of these flaws, please see our post on the Tenable TechBlog.

Get more information

• TRA-2022-19: Microsoft Azure Synapse Analytics Hosts File Poisoning
• TRA-2022-20: Microsoft Azure Synapse Analytics Privilege Escalation