Logcheck

This installation is done based on the proposed setup in Syslog.

Install

apt-get install logcheck logcheck-database

In /etc/logcheck/logcheck.conf:

INTRO=0
REPORTLEVEL="paranoid"
ADDTAG="yes"

In /etc/logcheck/logcheck.logfiles

/var/log/remote/MAIN/auth.log                                                                                                                                             
/var/log/remote/MAIN/syslog.log                                                                                                                                           
/var/log/remote/MAIN/kern.log                                                                                                                                             
/var/log/remote/mx/auth.log                                                                                                                                               
/var/log/remote/mx/syslog.log                                                                                                                                             
/var/log/remote/public/auth.log                                                                                                                                           
/var/log/remote/public/syslog.log                                                                                                                                         
/var/log/remote/private/auth.log                                                                                                                                          
/var/log/remote/private/syslog.log                                                                                                                                        
/var/log/remote/ns0/auth.log                                                                                                                                              
/var/log/remote/ns0/syslog.log                                                                                                                                            
/var/log/remote/sql/auth.log                                                                                                                                              
/var/log/remote/sql/syslog.log                                                                                                                                            
/var/log/remote/devel/auth.log                                                                                                                                            
/var/log/remote/devel/syslog.log                                                                                                                                          
#/var/log/remote/MAIN/NF/ethr_in.log                                                                                                                                      
/var/log/remote/MAIN/NF/ethr_out.log                                                                                                                                      
/var/log/remote/MAIN/NF/others.log

Because logrotate runs as cron.daily, e.g. 03:25 every day, we want logcheck to have run once just before (e.g. at xx:24) so I edit /etc/cron.d/logcheck:

24 * * * *       logcheck    if [ -x /usr/sbin/logcheck ]; then nice -n10 /usr/sbin/logcheck; fi

Tuning logcheck filters

Solving the issue at the source

I have many such messages in the vserver:

pam_limits[863]: setrlimit limit #6 to soft=-1, hard=-1 failed: Operation not permitted; uid=0 euid=0

Not sure why, probably because vserver max limits are reduced.
To get rid of it, comment the line in /etc/pam.d/cron and /etc/pam.d/ssh:

#session    required     pam_limits.so

Writing and testing new rules

Add your rules into files prepend by "local-" to distinguish your own rules.
Be sure to tune ownership and rights of those new files so that user logcheck can read them.
e.g. rw-r----- root:logcheck

To test logcheck filtering rules:

sed -e 's/[[:space:]]*$//' <logfile> | egrep '<regexp>'

Then you can dry run logcheck on the command line:

su logcheck -s /bin/bash -c "/usr/sbin/logcheck -l <logfile> -o -t" 

This is easier if you have sudo installed...

Examples of home-made rules

As I run in paranoid mode, I take some rules from server mode:

• /etc/logcheck/ignore.d.paranoid/local-sa-exim -> /etc/logcheck/ignore.d.server/sa-exim
• /etc/logcheck/ignore.d.paranoid/local-fetchmail -> /etc/logcheck/ignore.d.server/fetchmail

For imapd sessions:

/etc/logcheck/ignore.d.paranoid/local-imap:
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ imapd: Connection, ip=\[[:.0-9a-f]+\]$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ imapd: LOGIN, user=[a-z]+, ip=\[[:.0-9a-f]+\], protocol=IMAP$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ imapd: (TIMEOUT|LOGOUT), (user=[a-z]+, )?ip=\[[:.0-9a-f]+\], (headers=[0-9]+, body=[0-9]+, )?rcvd=[0-9]+, sent=[0-9]+(, time=[0-9]+)?(, starttls=1)?$

For imapproxy sessions:
Probably because of the templates in syslog-ng we have to change a bit the rules of ignore.d.server/imapproxy

/etc/logcheck/ignore.d.paranoid/local-imapproxy:
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ in.imapproxyd\[[0-9]+\]: LOGOUT: \\?'\\?"[_[:alnum:]-]+(@[-_.[:alnum:]]+)?\\?"\\?' from server sd \[[0-9]+\]$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ in.imapproxyd\[[0-9]+\]: LOGIN: \\?'\\?"[_[:alnum:]-]+(@[-_.[:alnum:]]+)?\\?"\\?'  \([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}:[0-9]+\) on (existing|new) sd \[[0-9]+\]$
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ in.imapproxyd\[[0-9]+\]: Expiring server sd \[[0-9]+\]$

For ssh just an excerpt from the ignore.d.server/ssh:

/etc/logcheck/ignore.d.paranoid/local-ssh:
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ sshd\[[0-9]+\]: Accepted (gssapi(-with-mic)?|rsa|dsa|password|publickey|keyboard-interactive/pam) for [^[:space:]]+ from [^[:space:]]+ port [0-9]+( (ssh|ssh2))?$