Backdoors give attackers unrestricted access to a zombie system. If you plan to stop the bad guys from settling in, you’ll be interested in this analysis of the tools they might use for building a private entrance.

Users log on to services such as SSH, ftp, SASL, POP3, IMAP, Apache htaccess, and many more using their names and passwords. These popular access mechanisms are a potential target for brute-force attacks. An attentive bouncer will keep dictionary attacks at bay.

If you are looking for an extra layer of remote access security, try single-packet port knocking.

The ancient Linux permission system is often insufficient for complex production environments. Access Control Lists offer a flexible alternative.

SELinux provides a safer system through the powerful concept of mandatory access controls.

Services that require a username and password for login are potential targets for dictionary attacks. Sshutout and Fail2ban introduce time penalties for invalid attempts.

The GnuTLS project has published two bugfix releases to close several vulnerabilities and resolve an error capable of interrupting connections.

The security and quality of Open Source software just keeps on improving, as code analysis by Coverity reveals.