During a routine security analysis, it was found that one of the ports in Apache Impala (incubating) 2.7.0 to 2.8.0 sent data in plaintext even when the cluster was configured to use TLS. The port in question was used by the StatestoreSubscriber class which did not use the appropriate secure Thrift transport when TLS was turned on. It was therefore possible for an adversary, with access to the network, to eavesdrop on the packets going to and coming from that port and view the data in plaintext.

It was noticed that a malicious process impersonating an Impala daemon in Apache Impala (incubating) 2.7.0 to 2.8.0 could cause Impala daemons to skip authentication checks when Kerberos is enabled (but TLS is not). If the malicious server responds with 'COMPLETE' before the SASL handshake has completed, the client will consider the handshake as completed even though no exchange of credentials has happened.