Every sysadmin will try its best to secure the system/s he is managing. Hopefully you never had to restore your own system from a compromise and you will not have to do this in the future. Working on several projects to restore a compromised Linux system for various clients, I have developed a set of rules that others might find useful in similar situations. The type of hacks encountered can be very variate and you might see very different ones than the one I will present, or I have seen live, but even so, this rules might be used as a starting point to develop your own recovery plan. . The link for this article located at Ducea.com is no longer available. . After a Linux server breach, isolate the server, investigate the cause, and clean malware. Secure systems with strong authentication and backups.. Linux Server Recovery, Hacked Server Restoration, Sysadmin Guidelines. . LinuxSecurity.com Team
The feeling you get in the pit of your stomach when you first suspect that your site has been cracked is similar to the feeling you get when you first discover your house has been broken into. It is a sickening sense of muted outrage.. . .. The feeling you get in the pit of your stomach when you first suspect that your site has been cracked is similar to the feeling you get when you first discover your house has been broken into. It is a sickening sense of muted outrage. Muted because you are still hoping against hope that it hasn't really happened. But your eyes are telling you that it has, that in spite of your denial you've been violated, that you're 0wn3d. Call it baud karma. Call it carelessness. Call it inevitable. I was 0wn3d and didn't know it. After downloading and installing BETA 21 of version 2.54 of NMAP (and its graphical frontend), I su'd to root, fired it up, and aimed a FIN stealth scan at ports 1-32000 on my server. I was running portsentry on the server, but my desktop machine -- the one I was running NMAP on -- was on the portsentry ignore list so that it wouldn't simply reroute my inquisitive packets to /dev/null after I hit the first protected port. The link for this article located at LinuxWorld is no longer available. . Confront the disquieting awareness of a data intrusion and examine remediation strategies utilizing NMAP methodologies.. Nmap, Site Security, Recovery Strategies, Incident Response, Network Testing. . LinuxSecurity.com Team
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