1. System logging and monitoring
CIS 238 Syslog
System logging and monitoring

2. Syslog
(r)syslog is a utility for tracking and logging all manner of system messages from the merely informational to the extremely critical. Sysogs stored in
In LINUX, system logs are stored in /var/log. System messages are recorded in /var/log/messages. Other OS’es may use different files in different directories (e.g. /var/adm).
Each system message sent to the syslog server has two descriptive labels associated with it that makes the message easier to handle.
- The first describes the function (facility) of the application that generated it. For example, applications such as mail and cron generate messages with easily identifiable facilities named mail and cron.
- The second describes the degree of severity of the message.

3. Syslog Severity: Level: Keyword: Description
0 emergencies System unusable
1 alerts Immediate action required
2 critical Critical condition
3 errors Error conditions
4 warnings Warning conditions
5 notifications Normal but significant conditions
6 informational Informational messages
7 debugging Debugging messages

4. Syslog
The files to which syslog writes each type of message received is set in the /etc/rsyslog.conf configuration file. In older versions of Fedora, this file was named /etc/syslog.conf.
This file consists of two columns. The first lists the facilities and severities of messages to expect and the second lists the files to which they should be logged. By default, RedHat/Fedora's /etc/rsyslog.conf file is configured to put most of the messages in the file /var/log/messages.
Example:
*.info;mail.none;authpriv.none;cron.none /var/log/messages
Note other services may record messages in other files (e.g. sendmail)
Syslog is also a network service. A common implementation is to forward system info to a common syslog server. See /etc/rsyslog.conf for client /server options
Logs compressed, ,stored and optionally ed by the logrotate function. Definitions stored in /etc/logrotate.conf and /etc/logrotate.d

5. Logrotate Log management for LINUX and UNIX
Basic config file is /etc/logrotate.conf
Individual package package config files in/etc/logrotate.d usually configured during package installation
Each config file specifies logfile list, rotate interval, rotation count, log size, compression options, postrotate command to perform a function after the log has been copied.

6. Logrotate automation UNIX systems require use of a specific CRON job
LINUX automatically includes logrotate in ANACRON.
ANACRON is an automatic CRON list created for system functions such as logtotate or tripwire. It is an extension of CRON.
See /etc files anacron, cron.daily, cron.weekly, cron.monthly. Also /var/spool/anacron

7. Logwatch Default freeware log monitoring tool Runs in Perl
Numerous other “pay for play” tools:
Logrobot
Nagios
Logstash
Graybar

8. Logwatch files System specific config: /etc/logwatch
Default config: /usr/share/logwatch/default.conf/
Distro specific config: /usr/share/logwatch/distro.conf/
Directories:
conf /*.conf, conf/logfiles, conf/services
scripts/services
Always copy default, distro files to local /etc/logwatch for modification
Priority sequence:
- /etc/logwatch
- /usr/share/logwatch/distro.conf
- /usr/share/logwatch/default.conf

9. Security today Governement regulations: HIPAA PCI-DSS SOX
No clear text applications – FTP, TELNET, NFS, RCP, RCMD, HTTP
Restricted access, minimum to do the job
Most legacy 3rd party apps are now commercial products:
- ssh
- Nagios
- Tripwire
- PGP
Some have freeware equivalents, but fewer over time.