Difference between revisions of "Syslog"

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==Logcheck==
 +
==Logrotate==
  +
We add a file to rotate our new log files:
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apt-get install logcheck logcheck-database
  
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/etc/logrotate.d/local-syslog-ng:
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In /etc/logcheck/logcheck.conf:
  
  +
/var/log/remote/*/*.log {
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INTRO=0
  
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rotate 28
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REPORTLEVEL="paranoid"
  
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missingok
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ADDTAG="yes"
  
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notifempty
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In /etc/logcheck/logcheck.logfiles
  
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daily
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/var/log/remote/MAIN/auth.log
 
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compress
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/var/log/remote/MAIN/syslog.log
 
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}
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/var/log/remote/MAIN/kern.log
 
  +
The call to syslog-ng reload will be done by the native /etc/logrotate.d/syslog-ng so we don't need to do it ourselves
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/var/log/remote/mx/auth.log
 
  +
==Others==
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/var/log/remote/mx/syslog.log
 
  +
Check [[Logcheck]] and [[Php-Syslog-ng]].
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/var/log/remote/public/auth.log
 
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/var/log/remote/public/syslog.log
 
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/var/log/remote/private/auth.log
 
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/var/log/remote/private/syslog.log
 
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/var/log/remote/ns0/auth.log
 
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/var/log/remote/ns0/syslog.log
 
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/var/log/remote/sql/auth.log
 
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/var/log/remote/sql/syslog.log
 
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/var/log/remote/devel/auth.log
 
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/var/log/remote/devel/syslog.log
 
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#/var/log/remote/MAIN/NF/ethr_in.log
 
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/var/log/remote/MAIN/NF/ethr_out.log
 
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/var/log/remote/MAIN/NF/others.log
 
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===Tuning logcheck filters===
  
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====Solving the issue at the source====
  
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I have many such messages in the vserver:
  
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pam_limits[863]: setrlimit limit #6 to soft=-1, hard=-1 failed: Operation not permitted; uid=0 euid=0
  
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Not sure why, probably because vserver max limits are reduced.
  
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<br>To get rid of it, comment the line in /etc/pam.d/cron and /etc/pam.d/ssh:
  
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#session required pam_limits.so
  
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====Writing and testing new rules====
  
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Add your rules into files prepend by "local-" to distinguish your own rules.
  
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<br>Be sure to tune ownership and rights of those new files so that user logcheck can read them.
  
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<br>e.g. rw-r----- root:logcheck
  
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To test logcheck filtering rules:
  
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<pre>
  
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sed -e 's/[[:space:]]*$//' <logfile> | egrep '<regexp>'
  
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</pre>
  
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Then you can dry run logcheck on the command line:
  
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su logcheck -s /bin/bash -c "/usr/sbin/logcheck -l <logfile> -o -t"
 
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This is easier if you have sudo installed...
  
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====Examples of home-made rules====
  
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As I run in paranoid mode, I take some rules from server mode:
  
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* /etc/logcheck/ignore.d.paranoid/local-sa-exim -> /etc/logcheck/ignore.d.server/sa-exim
  
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* /etc/logcheck/ignore.d.paranoid/local-fetchmail -> /etc/logcheck/ignore.d.server/fetchmail
  
−  
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For imapd sessions:
  
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/etc/logcheck/ignore.d.paranoid/local-imap:
  
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^\w{3} [ :0-9]{11} [._[:alnum:]-]+ imapd: Connection, ip=\[[:.0-9a-f]+\]$
  
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^\w{3} [ :0-9]{11} [._[:alnum:]-]+ imapd: LOGIN, user=[a-z]+, ip=\[[:.0-9a-f]+\], protocol=IMAP$
  
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^\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)?$
  
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For imapproxy sessions:
  
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<br>Probably because of the templates in syslog-ng we have to change a bit the rules of ignore.d.server/imapproxy
  
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/etc/logcheck/ignore.d.paranoid/local-imapproxy:
  
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^\w{3} [ :0-9]{11} [._[:alnum:]-]+ in.imapproxyd\[[0-9]+\]: LOGOUT: \\?'\\?"[_[:alnum:]-]+(@[-_.[:alnum:]]+)?\\?"\\?' from server sd \[[0-9]+\]$
  
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^\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 \[[0-9]+\]$
  
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^\w{3} [ :0-9]{11} [._[:alnum:]-]+ in.imapproxyd\[[0-9]+\]: Expiring server sd \[[0-9]+\]$
  
−  
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For ssh just an excerpt from the ignore.d.server/ssh:
  
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/etc/logcheck/ignore.d.paranoid/local-ssh:
  
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^\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))?$
  
−  
 
==TODO==
  
==TODO==
  ⚫
* source IP of zeus seems to be 100, why?
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* update syslog-ng notes with new filters, flag final etc
  
⚫
* source IP of zeus seems to be 100
  
 
* fwlogwatch?
  
* fwlogwatch?
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* http://www.phpwizardry.com/php-syslog-ng.php ?
  
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* logrotate
  

Latest revision as of 22:38, 24 November 2010

Syslog-ng

Install

apt-get install syslog-ng

Example of /etc/syslog-ng/syslog-ng.conf:

Comment kernel source out as we are in a vserver: 

   source s_all {
       #file("/proc/kmsg" log_prefix("kernel: "));

I want to keep the original hostnames: 

   options {
       keep_hostname(1);

Enable logging per remote host 

source net { udp(ip(<local_ip_or_hostname>)); };

Add specific destination files to collect auth.log and syslog.log of every remote (and local) node:
Note that for some we add a template to replace the IP by the hostname in the msgs 

destination df_zeus_auth      {   file("/var/log/remote/MAIN/auth.log"        owner("root") group("adm") perm(0640) template("$DATE MAIN $MESSAGE\n")); };
destination df_zeus_syslog    {   file("/var/log/remote/MAIN/syslog.log"      owner("root") group("adm") perm(0640) template("$DATE MAIN $MESSAGE\n")); };
destination df_zeus_kern      {   file("/var/log/remote/MAIN/kern.log"        owner("root") group("adm") perm(0640) template("$DATE MAIN $MESSAGE\n")); };
destination df_mx_auth        {   file("/var/log/remote/mx/auth.log"          owner("root") group("adm") perm(0640)); };
destination df_mx_syslog      {   file("/var/log/remote/mx/syslog.log"        owner("root") group("adm") perm(0640)); };
destination df_public_auth    {   file("/var/log/remote/public/auth.log"      owner("root") group("adm") perm(0640) template("$DATE public $MESSAGE\n")); };
destination df_public_syslog  {   file("/var/log/remote/public/syslog.log"    owner("root") group("adm") perm(0640) template("$DATE public $MESSAGE\n")); };
destination df_private_auth   {   file("/var/log/remote/private/auth.log"     owner("root") group("adm") perm(0640) template("$DATE private $MESSAGE\n")); };
destination df_private_syslog {   file("/var/log/remote/private/syslog.log"   owner("root") group("adm") perm(0640) template("$DATE private $MESSAGE\n")); };
destination df_ns0_auth       {   file("/var/log/remote/ns0/auth.log"         owner("root") group("adm") perm(0640) template("$DATE ns0 $MESSAGE\n")); };
destination df_ns0_syslog     {   file("/var/log/remote/ns0/syslog.log"       owner("root") group("adm") perm(0640) template("$DATE ns0 $MESSAGE\n")); };
destination df_sql_auth       {   file("/var/log/remote/sql/auth.log"         owner("root") group("adm") perm(0640) template("$DATE sql $MESSAGE\n")); };
destination df_sql_syslog     {   file("/var/log/remote/sql/syslog.log"       owner("root") group("adm") perm(0640) template("$DATE sql $MESSAGE\n")); };
destination df_devel_auth     {   file("/var/log/remote/devel/auth.log"       owner("root") group("adm") perm(0640) template("$DATE devel $MESSAGE\n")); };
destination df_devel_syslog   {   file("/var/log/remote/devel/syslog.log"     owner("root") group("adm") perm(0640) template("$DATE devel $MESSAGE\n")); };
destination df_others_auth    {   file("/var/log/remote/$HOST/auth.log"       owner("root") group("adm") perm(0640)); };
destination df_others_syslog  {   file("/var/log/remote/$HOST/syslog.log"     owner("root") group("adm") perm(0640)); };
destination df_nf_ethr_in     {   file("/var/log/remote/MAIN/NF/ethr_in.log"  owner("root") group("adm") perm(0640) template("$DATE MAIN $MESSAGE\n")); };
destination df_nf_ethr_out    {   file("/var/log/remote/MAIN/NF/ethr_out.log" owner("root") group("adm") perm(0640) template("$DATE MAIN $MESSAGE\n")); };
destination df_nf_others      {   file("/var/log/remote/MAIN/NF/others.log"   owner("root") group("adm") perm(0640) template("$DATE MAIN $MESSAGE\n")); };

Add filters for remote nodes:
This is quite strange but msgs from the host are seen as coming from the IP of the collecting node
As the source will be net instead of s_all, we can still distinguish both from each other
Filters are sub-string regexps so we have to pay attention that IP x.x.x.1 can catch IP x.x.x.100 if not ended with a $ 

filter f_zeus    { host(192.168.x.x$); };
filter f_public  { host(192.168.x.x$); };
filter f_private { host(192.168.x.x$); };
filter f_ns0     { host(192.168.x.x$); };
filter f_devel   { host(192.168.x.x$); };
filter f_sql     { host(192.168.x.x$); };

For the host which gets the kernel logs, we add filters for the netfilter logs: 

filter f_nf       { match("NF Dropped "); };
filter f_ethr_in  { match("ETH_R IN "); };
filter f_ethr_out { match("ETH_R OUT "); };

Then combine all those in log statements
They all contain the flag final so each entry will be captured only once, this avoids us to write negated filters and this should accelerate a bit the processing 

log {
        source(net);
        filter(f_zeus);
        filter(f_auth);
        destination(df_zeus_auth);
        flags(final);
};
log {
        source(net);
        filter(f_zeus);
        filter(f_kern);
        filter(f_nf);
        filter(f_ethr_in);
        destination(df_nf_ethr_in);
        flags(final);
};
log {
        source(net);
        filter(f_zeus);
        filter(f_kern);
        filter(f_nf);
        filter(f_ethr_out);
        destination(df_nf_ethr_out);
        flags(final);
};
log {
        source(net);
        filter(f_zeus);
        filter(f_kern);
        filter(f_nf);
        destination(df_nf_others);
        flags(final);
};
log {
        source(net);
        filter(f_zeus);
        filter(f_kern);
        destination(df_zeus_kern);
        flags(final);
};
log {
        source(net);
        filter(f_zeus);
        filter(f_syslog);
        destination(df_zeus_syslog);
        flags(final);
};
# Don't forget ourselves:
log {
        source(s_all);
        filter(f_auth);
        destination(df_mx_auth);
};
log {
        source(s_all);
        filter(f_syslog);
        destination(df_mx_syslog);
};
# Other vservers:
log {
        source(net);
        filter(f_public);
        filter(f_auth);
        destination(df_public_auth);
        flags(final);
};
log {
        source(net);
        filter(f_public);
        filter(f_syslog);
        destination(df_public_syslog);
        flags(final);
};
log {
        source(net);
        filter(f_private);
        filter(f_auth);
        destination(df_private_auth);
        flags(final);
};
log {
        source(net);
        filter(f_private);
        filter(f_syslog);
        destination(df_private_syslog);
        flags(final);
};
log {
        source(net);
        filter(f_ns0);
        filter(f_auth);
        destination(df_ns0_auth);
        flags(final);
};
log {
        source(net);
        filter(f_ns0);
        filter(f_syslog);
        destination(df_ns0_syslog);
        flags(final);
};
log {
        source(net);
        filter(f_sql);
        filter(f_auth);
        destination(df_sql_auth);
        flags(final);
};
log {
        source(net);
        filter(f_sql);
        filter(f_syslog);
        destination(df_sql_syslog);
        flags(final);
};
log {
        source(net);
        filter(f_devel);
        filter(f_auth);
        destination(df_devel_auth);
        flags(final);
};
log {
        source(net);
        filter(f_devel);
        filter(f_syslog);
        destination(df_devel_syslog);
        flags(final);
};
# Catch other remote hosts:
log {
        source(net);
        filter(f_auth);
        destination(df_others_auth);
        flags(final);
};
log {
        source(net);
        filter(f_syslog);
        destination(df_others_syslog);
        flags(final);
};

Allow inbound connections from monitoring subnet 

iptables -A INPUT -s xxxx -d xxxx -p udp --dport 514 -m state --state NEW -j ACCEPT

On satellite hosts: add to /etc/syslog.conf 

*.*               @192.168.x.xxx

Resources & Credits


Logrotate

We add a file to rotate our new log files: 

/etc/logrotate.d/local-syslog-ng:
/var/log/remote/*/*.log {
  rotate 28
  missingok
  notifempty
  daily
  compress
}

The call to syslog-ng reload will be done by the native /etc/logrotate.d/syslog-ng so we don't need to do it ourselves

Others

Check Logcheck and Php-Syslog-ng.

TODO

  • source IP of zeus seems to be 100, why?
  • fwlogwatch?
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