zimbra version is searchable on Shodan. For Example:
https://www.shodan.io/search?query=8.8.6_GA_1906
https://www.shodan.io/search?query=8.0.9_GA_6191
For "8.8.6_GA_1906" you will get an IMAP-Header like this:
Code: Select all
* OK IMAP4rev1 proxy server ready
* CAPABILITY ACL BINARY CATENATE CHILDREN CONDSTORE ENABLE ESEARCH ESORT I18NLEVEL=1 ID IDLE IMAP4rev1 LIST-EXTENDED LIST-STATUS LITERAL+ MULTIAPPEND NAMESPACE QRESYNC QUOTA RIGHTS=ektx SASL-IR SEARCHRES SORT THREAD=ORDEREDSUBJECT UIDPLUS UNSELECT WITHIN XLIST STARTTLS LOGINDISABLED
A001 OK completed
* ID ("NAME" "Zimbra" "VERSION" "8.8.6_GA_1906" "RELEASE" "20171130041047")
A002 OK completed
A003 BAD invalid command
A004 OK completed