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filter.d/sshd.conf: normalizing of user pattern in all RE's, allowing empty user (gh-2749)

pull/2814/head
sebres 2020-06-08 14:38:26 +02:00
parent 9b6da03c90
commit 5a0edf61c9
3 changed files with 14 additions and 8 deletions
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1
ChangeLog
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@ -56,6 +56,7 @@ ver. 0.10.6-dev (20??/??/??) - development edition
- `normal`: matches 401 with supplied username only
- `ddos`: matches 401 without supplied username only
- `aggressive`: matches 401 and any variant (with and without username)
* `filter.d/sshd.conf`: normalizing of user pattern in all RE's, allowing empty user (gh-2749)
### New Features
* new filter and jail for GitLab recognizing failed application logins (gh-2689)

16
config/filter.d/sshd.conf
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@ -25,7 +25,7 @@ __pref = (?:(?:error|fatal): (?:PAM: )?)?
__suff = (?: (?:port \d+|on \S+|\[preauth\])){0,3}\s*
__on_port_opt = (?: (?:port \d+|on \S+)){0,2}
# close by authenticating user:
__authng_user = (?: (?:invalid|authenticating) user <F-USER>\S+|.+?</F-USER>)?
__authng_user = (?: (?:invalid|authenticating) user <F-USER>\S+|.*?</F-USER>)?
# for all possible (also future) forms of "no matching (cipher|mac|MAC|compression method|key exchange method|host key type) found",
# see ssherr.c for all possible SSH_ERR_..._ALG_MATCH errors.
@ -44,18 +44,18 @@ cmnfailre = ^[aA]uthentication (?:failure|error|failed) for <F-USER>.*</F-USER>
^Failed <cmnfailed> for (?P<cond_inv>invalid user )?<F-USER>(?P<cond_user>\S+)|(?(cond_inv)(?:(?! from ).)*?|[^:]+)</F-USER> from <HOST>%(__on_port_opt)s(?: ssh\d*)?(?(cond_user): |(?:(?:(?! from ).)*)$)
^<F-USER>ROOT</F-USER> LOGIN REFUSED FROM <HOST>
^[iI](?:llegal|nvalid) user <F-USER>.*?</F-USER> from <HOST>%(__suff)s$
^User <F-USER>.+</F-USER> from <HOST> not allowed because not listed in AllowUsers%(__suff)s$
^User <F-USER>.+</F-USER> from <HOST> not allowed because listed in DenyUsers%(__suff)s$
^User <F-USER>.+</F-USER> from <HOST> not allowed because not in any group%(__suff)s$
^User <F-USER>\S+|.*?</F-USER> from <HOST> not allowed because not listed in AllowUsers%(__suff)s$
^User <F-USER>\S+|.*?</F-USER> from <HOST> not allowed because listed in DenyUsers%(__suff)s$
^User <F-USER>\S+|.*?</F-USER> from <HOST> not allowed because not in any group%(__suff)s$
^refused connect from \S+ \(<HOST>\)
^Received <F-MLFFORGET>disconnect</F-MLFFORGET> from <HOST>%(__on_port_opt)s:\s*3: .*: Auth fail%(__suff)s$
^User <F-USER>.+</F-USER> from <HOST> not allowed because a group is listed in DenyGroups%(__suff)s$
^User <F-USER>.+</F-USER> from <HOST> not allowed because none of user's groups are listed in AllowGroups%(__suff)s$
^User <F-USER>\S+|.*?</F-USER> from <HOST> not allowed because a group is listed in DenyGroups%(__suff)s$
^User <F-USER>\S+|.*?</F-USER> from <HOST> not allowed because none of user's groups are listed in AllowGroups%(__suff)s$
^<F-NOFAIL>%(__pam_auth)s\(sshd:auth\):\s+authentication failure;</F-NOFAIL>(?:\s+(?:(?:logname|e?uid|tty)=\S*)){0,4}\s+ruser=<F-ALT_USER>\S*</F-ALT_USER>\s+rhost=<HOST>(?:\s+user=<F-USER>\S*</F-USER>)?%(__suff)s$
^maximum authentication attempts exceeded for <F-USER>.*</F-USER> from <HOST>%(__on_port_opt)s(?: ssh\d*)?%(__suff)s$
^User <F-USER>.+</F-USER> not allowed because account is locked%(__suff)s
^User <F-USER>\S+|.*?</F-USER> not allowed because account is locked%(__suff)s
^<F-MLFFORGET>Disconnecting</F-MLFFORGET>(?: from)?(?: (?:invalid|authenticating)) user <F-USER>\S+</F-USER> <HOST>%(__on_port_opt)s:\s*Change of username or service not allowed:\s*.*\[preauth\]\s*$
^Disconnecting: Too many authentication failures(?: for <F-USER>.+?</F-USER>)?%(__suff)s$
^Disconnecting: Too many authentication failures(?: for <F-USER>\S+|.*?</F-USER>)?%(__suff)s$
^<F-NOFAIL>Received <F-MLFFORGET>disconnect</F-MLFFORGET></F-NOFAIL> from <HOST>%(__on_port_opt)s:\s*11:
<mdre-<mode>-other>
^<F-MLFFORGET><F-MLFGAINED>Accepted \w+</F-MLFGAINED></F-MLFFORGET> for <F-USER>\S+</F-USER> from <HOST>(?:\s|$)

5
fail2ban/tests/files/logs/sshd
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@ -321,6 +321,11 @@ Mar 15 09:21:02 host sshd[2717]: Connection closed by 192.0.2.212 [preauth]
# failJSON: { "time": "2005-07-18T17:19:11", "match": true , "host": "192.0.2.4", "desc": "ddos: disconnect on preauth phase, gh-2115" }
Jul 18 17:19:11 srv sshd[2101]: Disconnected from 192.0.2.4 port 36985 [preauth]
# failJSON: { "time": "2005-06-06T04:17:04", "match": true , "host": "192.0.2.68", "dns": null, "user": "", "desc": "empty user, gh-2749" }
Jun 6 04:17:04 host sshd[1189074]: Invalid user from 192.0.2.68 port 34916
# failJSON: { "time": "2005-06-06T04:17:09", "match": true , "host": "192.0.2.68", "dns": null, "user": "", "desc": "empty user, gh-2749" }
Jun 6 04:17:09 host sshd[1189074]: Connection closed by invalid user 192.0.2.68 port 34916 [preauth]
# filterOptions: [{"mode": "extra"}, {"mode": "aggressive"}]
# several other cases from gh-864: