I'm looking for some help with this problem. I'd like to have fail2ban block systems trying to authenticate via smtp or imap. However, for known users I get: Jan 28 13:33:36 mail auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=frank rhost=189.22.108.130 user=known_user Jan 28 13:33:37 mail auth: pam_sss(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=frank rhost=189.22.108.130 user=known_user and for unknown users I get: Jan 28 13:27:16 mail auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=unknown_user rhost=189.22.108.130 so I can't key off of the pam_unix messages because that will lock out known users, and keying off of pam_sss will only block attacks that guess a correct username. Is there some way I can get pam_sss to log the unknown user attempts?

-- Orion Poplawski Technical Manager 303-415-9701 x222 NWRA, Boulder/CoRA Office FAX: 303-415-9702 3380 Mitchell Lane orion(a)nwra.com Boulder, CO 80301 http://www.nwra.com _______________________________________________ sssd-users mailing list sssd-users(a)lists.fedorahosted.org https://lists.fedorahosted.org/mailman/listinfo/sssd-users

On 01/29/2015 01:47 AM, Sumit Bose wrote: > On Wed, Jan 28, 2015 at 03:11:15PM -0700, Orion Poplawski wrote: >> I'm looking for some help with this problem. I'd like to have >> fail2ban block >> systems trying to authenticate via smtp or imap. However, for known >> users I get: >> >> Jan 28 13:33:36 mail auth: pam_unix(dovecot:auth): authentication >> failure; >> logname= uid=0 euid=0 tty=dovecot ruser=frank rhost=189.22.108.130 >> user=known_user >> Jan 28 13:33:37 mail auth: pam_sss(dovecot:auth): authentication >> failure; >> logname= uid=0 euid=0 tty=dovecot ruser=frank rhost=189.22.108.130 >> user=known_user >> >> and for unknown users I get: >> >> Jan 28 13:27:16 mail auth: pam_unix(dovecot:auth): authentication >> failure; >> logname= uid=0 euid=0 tty=dovecot ruser=unknown_user >> rhost=189.22.108.130 >> >> so I can't key off of the pam_unix messages because that will lock >> out known >> users, and keying off of pam_sss will only block attacks that guess >> a correct >> username. Is there some way I can get pam_sss to log the unknown >> user attempts? > > How does your full pam configuration looks like. E.g. on Fedora I have a > > auth requisite pam_succeed_if.so uid >= 1000 quiet_success > > line between pam_unix and pam_sss. Since the user is not known it will > not have a uid and not go pass this line. auth required pam_env.so auth sufficient pam_unix.so nullok try_first_pass auth requisite pam_succeed_if.so uid >= 500 quiet auth sufficient pam_sss.so use_first_pass auth required pam_deny.so What you say doesn't make sense to me though. As I read the docs, if uid < 500 (as returned by pam_unix), pam_succeed_if will fail and stop pam processing, so as to prevent authenticating system users against sss. But if uid >= 500, it continues on to pam_sss. For unknown users (no uid), it would seem to me that it would have to continue on to sss, otherwise how would you authenticate users not in /etc/passwd? It just appears to me that pam_sss is not logging attempts by unknown users, and I'm not sure why.