Today my honeypot has been capturing scans for the Hazelcast REST API. I checked my logs for the past 2 years and these only started today. The last vulnerability published for Hazelcast was CVE-2018-10654 and related to "There is a Hazelcast Library Java Deserialization Vulnerability in Citrix XenMobile Server 10.8 before RP2 and 10.7 before RP3."[3]

There was some discussion regarding this issue at the end of Sep 2019 that got fixed at the end of Nov 2019 [5] where /hazelcast/rest/cluster HTTP endpoint returns HTTP 500 status. If you are seeing similar discovery scans and when they started, we would like to hear from you.

[1] https://docs.hazelcast.org/docs/management-center/3.9.2/manual/html/Clustered_REST_via_Management_Center.html
[2] https://vulmon.com/searchpage?q=hazelcast
[3] https://vulmon.com/vulnerabilitydetails?qid=CVE-2018-10654&scoretype=cvssv2
[4] https://github.com/hazelcast/hazelcast/issues/15635
[5] https://github.com/hazelcast/hazelcast/pull/16150
[6] https://isc.sans.edu/forums/diary/Citrix+ADC+Exploits+Overview+of+Observed+Payloads/25704

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Guy Bruneau IPSS Inc.
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Twitter: GuyBruneau
gbruneau at isc dot sans dot edu