This is Part 2 of a GoGrid security blog series on identifying and recovering from a Linux security breach. Part 1 provided general guidelines for conducting a security analysis on a compromised Linux server and forming strategic teams to address and resolve the breach.

In this article, we’ll review some recommended steps for recovering from a breach.

Recovering from the Breach

Lock the doors

Now that you’ve confirmed that there are no intruders logged in and you’ve identified the established connections, it’s time to “lock the doors.” Locking the doors largely depends on who is managing your firewall. Contact GoGrid in the event that we’re managing your firewall or perform the following actions if you manage your firewall:

• Modify your system’s iptables configuration to restrict all remote console connections such as SSH to your office network
• Modify your system’s iptables configuration to block all previously identified suspicious connections from and to your system.
• Modify your system’s iptables to block all other services from the public Internet to your server. Doing so will effectively bring down your website or services, but you want to avoid compromising your customers or web site visitors.

Install and run a rootkit analyzer

(more…) «How to Recover from a Linux Security Breach – Recovery & Hardening (Part 2)»

This 2-part GoGrid security blog series provides general guidelines for conducting a security analysis on a compromised Linux server and for recovering from a breach. Before you begin the security analysis, you need to consider two important factors:

1. The type of data your compromised server is storing or transmitting,
2. How important the server’s function is to your business

The data type—Personally Identifiable Information (PII) or Protected Health Information (PHI), for example—is important because your organization could be legally required to notify external parties and local or federal government agencies in the event of a breach. The compromised server’s function is important because its criticality may drive the recovery timeline.

You also may want to consider engaging a third-party that specializes in security forensics.

This series will cover 3 important items:

1) Understanding & assessing the breach
2) Setting up forensics & recovery teams
3) Recovering from the breach

Although this series won’t replace what a competent security firm can accomplish, it does provide an overview of some core processes, procedures, and activities you can do to potentially recover from a breach. And because each incident varies based on your computer system, be sure to conduct additional analysis and consult with experts to double-check your breach identification and resolution plan. (more…) «How to Recover from a Linux Security Breach – Forensics, Analysis, & Building Teams (Part 1)»