Synopsis
Tenable Research has discovered a flaw that allows a user to poison the hosts file on all nodes in their pool, which allows one to redirect subsets of traffic and snoop on services users generally do not have access to.
There exists a service on one of the hosts in each Spark pool called “HostResolver.” To be specific, it can be found at “/opt/microsoft/Microsoft.Analytics.Clusters.Services.HostResolver.dll” on each of the nodes in the Synapse environment. This service is used to manage the “hosts” file for all hosts in the Spark cluster. Due to the lack of any authentication features, a low-privileged user is able to overwrite the “hosts” file on all nodes in their Spark pool, which allows them to snoop on services and traffic they otherwise are not intended to be able to see.
For more details, please see our Tenable Techblog entry.
Solution
No known solution is available at this time.
Additional References
https://medium.com/tenable-techblog/microsoft-azure-synapse-pwnalytics-87c99c036291Disclosure Timeline
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