Re: [CentOS] saslauthd attack
On Wed, 2010-02-10 at 22:33 -0500, John Hinton wrote: Yes... most of them. Just the new PITA. Anyway... I still can't seem to figure out how to log the IP addresses for this attack. The system is saslauthd running as a service... sendmail and dovecot setup. I have log levels in sendmail set to 14. Something has to be able to log the offender(s). Any ideas what I'm missing or where to look? John Lincoln Zuljewic Silva wrote: I supose that you are using SMTP authentication with SASL. From the log service=smtp...so, in fact, the attack is coming from the SMTP server and not directly to the SASL. I guess that someone is trying to do a brute force attack on the SMTP server. Regards Lincoln On Wed, Feb 10, 2010 at 6:08 PM, John Hinton webmas...@ew3d.com wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: snip I use denyhosts which has worked well for me. I have two IPs which have been under attack mostly on ssh, some on dovecot, periodically for the last six weeks. Offending IPs are logged when blocked, but they just switch IPs as well as login user names. At least with denyhosts the IPs are readily available. Cheers. B.J. CentOS 5.4, Linux 2.6.18-164.11.1.el5 athlon 05:24:40 up 9:38, 1 user, load average: 0.33, 0.17, 0.19 ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
[CentOS] saslauthd attack
I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
I supose that you are using SMTP authentication with SASL. From the log service=smtp...so, in fact, the attack is coming from the SMTP server and not directly to the SASL. I guess that someone is trying to do a brute force attack on the SMTP server. Regards Lincoln On Wed, Feb 10, 2010 at 6:08 PM, John Hinton webmas...@ew3d.com wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Lincoln Zuljewic Silva More contact info.: http://www.system.adm.br/contact.php How often must a question be asked before it’s considered a frequently asked question? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
Yes... most of them. Just the new PITA. Anyway... I still can't seem to figure out how to log the IP addresses for this attack. The system is saslauthd running as a service... sendmail and dovecot setup. I have log levels in sendmail set to 14. Something has to be able to log the offender(s). Any ideas what I'm missing or where to look? John Lincoln Zuljewic Silva wrote: I supose that you are using SMTP authentication with SASL. From the log service=smtp...so, in fact, the attack is coming from the SMTP server and not directly to the SASL. I guess that someone is trying to do a brute force attack on the SMTP server. Regards Lincoln On Wed, Feb 10, 2010 at 6:08 PM, John Hinton webmas...@ew3d.com wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
Perhaps you can use netstat to identify who is currently connected to the machine. Then run it several times over a short period and block the most likely culprits ? John Hinton wrote: Yes... most of them. Just the new PITA. Anyway... I still can't seem to figure out how to log the IP addresses for this attack. The system is saslauthd running as a service... sendmail and dovecot setup. I have log levels in sendmail set to 14. Something has to be able to log the offender(s). Any ideas what I'm missing or where to look? John Lincoln Zuljewic Silva wrote: I supose that you are using SMTP authentication with SASL. From the log service=smtp...so, in fact, the attack is coming from the SMTP server and not directly to the SASL. I guess that someone is trying to do a brute force attack on the SMTP server. Regards Lincoln On Wed, Feb 10, 2010 at 6:08 PM, John Hinton webmas...@ew3d.com wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
John Hinton wrote: Yes... most of them. Just the new PITA. Anyway... I still can't seem to figure out how to log the IP addresses for this attack. I'd use iptables to log connections on that port and then time-correlate with the log entries from saslauthd. Best, --- Les Bell [http://www.lesbell.com.au] Tel: +61 2 9451 1144 ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
I am running IPTraf and have one offender... not a problem to find the address by hand, but I know these things grow. Years ago it was ssh... they are still trying. Then FTP... then smtp... but I have not before seen one like this where I can't find it logged... and I want to put into place some automated scripts to deal with it immediately. As the kiddie scripts seem to go, with time, there is a need to kill off such things before you have 10,000 systems out there trying to authenticate once every second or two. It is dictionary as it has changed to alias from anna now. LOL!!! They aren't going to get in... just wasting resources. John Clint Dilks wrote: Perhaps you can use netstat to identify who is currently connected to the machine. Then run it several times over a short period and block the most likely culprits ? John Hinton wrote: Yes... most of them. Just the new PITA. Anyway... I still can't seem to figure out how to log the IP addresses for this attack. The system is saslauthd running as a service... sendmail and dovecot setup. I have log levels in sendmail set to 14. Something has to be able to log the offender(s). Any ideas what I'm missing or where to look? John Lincoln Zuljewic Silva wrote: I supose that you are using SMTP authentication with SASL. From the log service=smtp...so, in fact, the attack is coming from the SMTP server and not directly to the SASL. I guess that someone is trying to do a brute force attack on the SMTP server. Regards Lincoln On Wed, Feb 10, 2010 at 6:08 PM, John Hinton webmas...@ew3d.com wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] saslauthd attack
On Wed, 2010-02-10 at 15:08 -0500, John Hinton wrote: I'm seeing a lot of activity over the last two days with what looks to be a kiddie script. Mostly trying to access several of our servers with the username anna. All failed... in fact I don't think we have a user anna on any of our servers. Meanwhile... I'm running Sendmail. This pertains to Centos 4 and 5 servers. I'm also running fail2ban on some and Ossec on others. So far, no blocking is being done. When I look at the logs all I find is under messages and here is a sample: Feb 10 05:23:08 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:25 neptune saslauthd[3369]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 05:23:58 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:53 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:54 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:55 neptune saslauthd[3370]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Feb 10 06:56:59 neptune saslauthd[3368]: do_auth : auth failure: [user=anna] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] So, I can't write a rule to block this attack as I can't find any IP address to block. I've looked and googled til my eyes are red and can't find where to set logging in saslauthd or where ever it needs to be set to record the IP address generating these failures. Does anyone have an idea? Also, some may wish to do a grep 'do_auth' on messages to see if this is happening to you. They sometimes come in rapid succession. John Hinton ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos In my case the last one was on 19th of January, and came from an IP in China 118-167-9-72.dynamic.hinet.net [118.167.9.72]. Took it from /var/spool/maillog. Actually I'm running Postfix with sasl, and the portion of maillog I was looking for was: SASL LOGIN authentication failed. Don't know how it will be on sendmail, though. HTH, Calin Key fingerprint = 37B8 0DA5 9B2A 8554 FB2B 4145 5DC1 15DD A3EF E857 = Does it worry you that you don't talk any kind of sense? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
