diff --git a/config/filter.d/sshd.conf b/config/filter.d/sshd.conf index 320ab59c..95915fcc 100644 --- a/config/filter.d/sshd.conf +++ b/config/filter.d/sshd.conf @@ -37,24 +37,24 @@ cmnfailre = ^[aA]uthentication (?:failure|error|failed) for .* ^User .+ from not allowed because listed in DenyUsers\s*%(__suff)s$ ^User .+ from not allowed because not in any group\s*%(__suff)s$ ^refused connect from \S+ \(\)\s*%(__suff)s$ - ^Received disconnect from %(__on_port_opt)s:\s*3: .*: Auth fail%(__suff)s$ + ^Received disconnect from %(__on_port_opt)s:\s*3: .*: Auth fail%(__suff)s$ ^User .+ from not allowed because a group is listed in DenyGroups\s*%(__suff)s$ ^User .+ from not allowed because none of user's groups are listed in AllowGroups\s*%(__suff)s$ ^pam_unix\(sshd:auth\):\s+authentication failure;\s*logname=\S*\s*uid=\d*\s*euid=\d*\s*tty=\S*\s*ruser=\S*\s*rhost=\s.*%(__suff)s$ ^(error: )?maximum authentication attempts exceeded for .* from %(__on_port_opt)s(?: ssh\d*)?%(__suff)s$ ^User .+ not allowed because account is locked%(__suff)s - ^Disconnecting: Too many authentication failures(?: for .+?)?%(__suff)s - ^Received disconnect from : 11: - ^Connection closed by %(__suff)s$ + ^Disconnecting: Too many authentication failures(?: for .+?)?%(__suff)s + ^Received disconnect from : 11: + ^Connection closed by %(__suff)s$ mdre-normal = mdre-ddos = ^Did not receive identification string from %(__suff)s$ - ^Connection reset by %(__on_port_opt)s%(__suff)s + ^Connection reset by %(__on_port_opt)s%(__suff)s ^SSH: Server;Ltype: (?:Authname|Version|Kex);Remote: -\d+;[A-Z]\w+: - ^Read from socket failed: Connection reset by peer%(__suff)s + ^Read from socket failed: Connection reset by peer%(__suff)s -mdre-extra = ^Received disconnect from %(__on_port_opt)s:\s*14: No supported authentication methods available%(__suff)s$ +mdre-extra = ^Received disconnect from %(__on_port_opt)s:\s*14: No supported authentication methods available%(__suff)s$ ^Unable to negotiate with %(__on_port_opt)s: no matching (?:cipher|key exchange method) found. ^Unable to negotiate a (?:cipher|key exchange method)%(__suff)s$ diff --git a/fail2ban/server/filter.py b/fail2ban/server/filter.py index ca2dae86..cbdb4857 100644 --- a/fail2ban/server/filter.py +++ b/fail2ban/server/filter.py @@ -554,20 +554,29 @@ class Filter(JailThread): mlfidGroups = mlfidFail[1] # if current line not failure, but previous was failure: if fail.get('nofail') and not mlfidGroups.get('nofail'): - del fail['nofail'] # remove nofail flag - was already market as failure + del fail['nofail'] # remove nofail flag - completed with fid (host, ip) self.mlfidCache.unset(mlfid) # remove cache entry # if current line is failure, but previous was not: elif not fail.get('nofail') and mlfidGroups.get('nofail'): - del mlfidGroups['nofail'] # remove nofail flag + del mlfidGroups['nofail'] # remove nofail flag - completed as failure self.mlfidCache.unset(mlfid) # remove cache entry + else: + # cache this line info (if not forget): + if not fail.get('mlfforget'): + mlfidFail = [self.__lastDate, fail] + self.mlfidCache.set(mlfid, mlfidFail) + else: + self.mlfidCache.unset(mlfid) # remove cache entry + return fail fail2 = mlfidGroups.copy() fail2.update(fail) fail2["matches"] = fail.get("matches", []) + failRegex.getMatchedTupleLines() fail = fail2 - elif fail.get('nofail'): - fail["matches"] = failRegex.getMatchedTupleLines() + elif not fail.get('mlfforget'): mlfidFail = [self.__lastDate, fail] self.mlfidCache.set(mlfid, mlfidFail) + if fail.get('nofail'): + fail["matches"] = failRegex.getMatchedTupleLines() return fail @@ -683,6 +692,11 @@ class Filter(JailThread): mlfid = fail.get('mlfid') if mlfid is not None: fail = self._mergeFailure(mlfid, fail, failRegex) + # bypass if no-failure case: + if fail.get('nofail'): + logSys.log(7, "Nofail by mlfid %r in regex %s: waiting for failure", + mlfid, failRegexIndex) + if not self.checkAllRegex: return failList else: # matched lines: fail["matches"] = fail.get("matches", []) + failRegex.getMatchedTupleLines() @@ -702,18 +716,16 @@ class Filter(JailThread): host = fail.get('dns') if host is None: # first try to check we have mlfid case (cache connection id): - if fid is None: - if mlfid: - fail = self._mergeFailure(mlfid, fail, failRegex) - else: + if fid is None and mlfid is None: # if no failure-id also (obscure case, wrong regex), throw error inside getFailID: fid = failRegex.getFailID() host = fid cidr = IPAddr.CIDR_RAW # if mlfid case (not failure): if host is None: - if not self.checkAllRegex: # or fail.get('nofail'): - return failList + logSys.log(7, "No failure-id by mlfid %r in regex %s: waiting for identifier", + mlfid, failRegexIndex) + if not self.checkAllRegex: return failList ips = [None] # if raw - add single ip or failure-id, # otherwise expand host to multiple ips using dns (or ignore it if not valid): diff --git a/fail2ban/tests/files/logs/sshd b/fail2ban/tests/files/logs/sshd index fe19591c..6f9a1468 100644 --- a/fail2ban/tests/files/logs/sshd +++ b/fail2ban/tests/files/logs/sshd @@ -113,6 +113,11 @@ May 27 00:16:33 host sshd[2364]: Received disconnect from 198.51.100.76: 11: Bye # failJSON: { "time": "2004-09-29T16:28:02", "match": true , "host": "127.0.0.1" } Sep 29 16:28:02 spaceman sshd[16699]: Failed password for dan from 127.0.0.1 port 45416 ssh1 +# failJSON: { "match": false, "desc": "no failure, just cache mlfid (conn-id)" } +Sep 29 16:28:05 localhost sshd[16700]: Connection from 192.0.2.5 +# failJSON: { "match": false, "desc": "no failure, just covering mlfid (conn-id) forget" } +Sep 29 16:28:05 localhost sshd[16700]: Connection closed by 192.0.2.5 [preauth] + # failJSON: { "time": "2004-09-29T17:15:02", "match": true , "host": "127.0.0.1" } Sep 29 17:15:02 spaceman sshd[12946]: Failed hostbased for dan from 127.0.0.1 port 45785 ssh2: RSA 8c:e3:aa:0f:64:51:02:f7:14:79:89:3f:65:84:7c:30, client user "dan", client host "localhost.localdomain"