PerSourcePenalties
This allows penalising connection sources that have had connections
dropped by the RefuseConnection option. ok markus@
OpenBSD-Commit-ID: 3c8443c427470bb3eac1880aa075cb4864463cb6
If set, this will terminate the connection at the first authentication
request (this is the earliest we can evaluate sshd_config Match blocks)
ok markus@
OpenBSD-Commit-ID: 43cc2533984074c44d0d2f92eb93f661e7a0b09c
problematic client behaviours, controlled by two new sshd_config(5) options:
PerSourcePenalties and PerSourcePenaltyExemptList.
When PerSourcePenalties are enabled, sshd(8) will monitor the exit
status of its child pre-auth session processes. Through the exit
status, it can observe situations where the session did not
authenticate as expected. These conditions include when the client
repeatedly attempted authentication unsucessfully (possibly indicating
an attack against one or more accounts, e.g. password guessing), or
when client behaviour caused sshd to crash (possibly indicating
attempts to exploit sshd).
When such a condition is observed, sshd will record a penalty of some
duration (e.g. 30 seconds) against the client's address. If this time
is above a minimum threshold specified by the PerSourcePenalties, then
connections from the client address will be refused (along with any
others in the same PerSourceNetBlockSize CIDR range).
Repeated offenses by the same client address will accrue greater
penalties, up to a configurable maximum. A PerSourcePenaltyExemptList
option allows certain address ranges to be exempt from all penalties.
We hope these options will make it significantly more difficult for
attackers to find accounts with weak/guessable passwords or exploit
bugs in sshd(8) itself.
PerSourcePenalties is off by default, but we expect to enable it
automatically in the near future.
much feedback markus@ and others, ok markus@
OpenBSD-Commit-ID: 89ded70eccb2b4926ef0366a4d58a693de366cca
options which provide more fine grained MaxStartups limits. Man page help
jmc@, feedback & ok djm@
OpenBSD-Commit-ID: e2f68664e3d02c0895b35aa751c48a2af622047b
