Running rkhunter (v1.4.2) from stretch on multiple servers.
SSH protocol 1 was removed in the openssh version that ships with stretch (v7.4): https://lists.mindrot.org/pipermail/openssh-unix-dev/2016-May/035069.html
That being said: I'm running with a commented #ALLOW_SSH_PROT_V1=0 (which is the default upstream). According to the documentation: A value of '0' indicates that the use of SSH-1 is not allowed.
Offending line: https://sources.debian.org/src/rkhunter/1.4.6-5/files/rkhunter.conf/ line 323.
Bug resolution: change the line to the default value of 0 and comment it out for future use (basically pull the line straight from upstream).
