Centos Security

1. Centos Security
By Yasin
yasin@yasin.my

2. Linux Security Checklist
• Add Users and Passwords
• Read, Write, and Execute Permissions
• Protect root
• Use Trusted Software
• Get Software Updates
• Use Secure Applications
• Use Restrictive Firewalls
• Enable Only Services You Need

3. Linux Security Checklist
• Limit Access to Services
• Check Your System
• Monitor Your System
• Use SELinux
• The centos-announce List
(http://lists.centos.org/)
• Red Hat Security Alerts
(www.redhat.com/security)

4. Using the Security Level
ConfigurationWindow
• Set up a basic firewall using the Security Level
Configuration window.
• Trusted Services— You can open access to
ports associated with your network interfaces to
provide the services you want to make available
from your system. Some services, such as
Samba, require that multiple ports be open.
• Other Ports—You can allow access to any other
port numbers by adding them to the ‘‘Other
ports’’ box

5. Using the ssh, sftp, and scp
commands
• Three commands you can use with the
SSH service are ssh, sftp, and scp.
Remote users use the ssh command to
log in to your system securely. The scp
command lets remote users copy files to
and from a system. The sftp command
provides a safe way to access secure
SFTP sites.

6. Understanding Attack Techniques
• Denial of Service (DOS)
• Distributed Denial of Service (DDOS)
• Intrusion Attacks

7. Protecting against Denial-of-
Service Attacks
• attack attempts to crash your computer or
at least degrade its performance to an
unusable level.
• Mailbombing - e-mail-filtering tool
• Smurf Amplification Attack (flooding your
Internet connection) - The best fix is to
contact the organization being used as a
relay and inform them of the abuse.

8. Protecting against Distributed DOS
Attacks
• much harder to initiate and nearly
impossible to stop.
• The best way to defend yourself is to
contact your ISP and see if it can filter the
traffic at its border routers.

9. Protecting against Intrusion Attacks
• Intrusion attacks focus on exploiting
weaknesses in your security
• Disabling Network Services
• Securing Servers with SELinux
• Protecting Web Servers with Certificates
and Encryption

10. Thank you
• http://www.yasin.my