EMpulse Group

Nice Cacti Install How To

admin — Tue, 21 Apr 2009 15:25:22 +0000

RedHat / CentOS Install and Configure Cacti Network Graphing Tool

Reset file permissions of RPM packages

admin — Fri, 17 Apr 2009 04:55:43 +0000

A disastrous mistake anyone can make on their Linux server is to chown or chmod their entire filesystem.

You can reset the permissions of packages installed with rpm.

To reset file permissions:

root@empulse:$ rpm --setperms {packagename}

To reset ownership permissions:

root@empulse:$ rpm --setugids {packagename}

Security Articles

admin — Sun, 05 Apr 2009 20:15:31 +0000

Hacking-Gurus: Network and Server Security Blog really has some useful information documented. Check out these articles.

Basic Linux Server Security

Linux Security Tools

SQL CheatSheet

SQL Injection article

admin — Sun, 05 Apr 2009 20:00:13 +0000

This is an article I found on Twitter from Hacking-Gurus on SQL injection. Check it out.

MySQL: Secure Web Apps – SQL Injection techniques

One-Liners

admin — Sun, 05 Apr 2009 00:00:45 +0000

Search for multiple processes in one command. Example in using multiple variables.

root@empulse:$ ps auxf | grep -P '(wincompd:|proftpd:)'

Lower the reserved disk space to 0%. By default Linux will reserve 5% of each file system as reserve free disk space.

root@empulse:$ tune2fs -m 0 /dev/hda5 remove reserved space

Compare two files on two remote file systems. I saw this on Command-line-fu.

root@empulse:$ diff <(ssh alice cat /etc/apt/sources.list) <(ssh bob cat /etc/apt/sources.list)

Frequently used Linux one-liners

admin — Mon, 30 Mar 2009 15:55:26 +0000

I just submitted a couple of one-liners that I frequently use to Command-line-Fu.

Find brute force attempts on SSHd – Searches the /var/log/secure log file for Failed and/or invalid user log in attempts.

root@empulse:$ cat /var/log/secure | grep sshd | grep Failed | sed 's/invalid//' | sed 's/user//' | awk '{print $11}' | sort | uniq -c | sort -n

List SMTP connections by host – Searches /var/log/secure for smtp connections then lists these by number of connections made and hosts.

root@empulse:$ cat /var/log/secure | grep smtp | awk '{print $9}' | cut -f2 -d= | sort | uniq -c | sort -n | tail

Command-line-Fu

admin — Mon, 30 Mar 2009 05:28:51 +0000

If you haven’t seen this site you need to check it out. Command-line-Fu is running list of submitted Linux one-liner commands. Some of these are really cool and you can of course submit your own for peer review.

Here are a couple of examples you may find.

Update twitter via curl

username@computername:$ curl -u user:pass -d status="Tweeting from the shell" http://twitter.com/statuses/update.xml

List of commands you use most often

username@computername:$ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head

Linux Security Quick Reference Guide

admin — Mon, 30 Mar 2009 04:17:32 +0000

I just found this quick reference sheet on Linux security topics from Apache and DNS security to crucial system files, tcp wrappers, and configuring syslog. This document from LinuxSecurity.com is available as a pdf download is provided below.

Linux Security Quick Reference Guide (pdf)

Excerpt: “Regularly audit your systems for any unauthorized and unnecessary use of the setuid or setgid permissions.”

Quick tip: Find all setuid and setgid programs

root# find / -type f -perm +6000 -ls

How do you linux? Contest

admin — Fri, 27 Mar 2009 19:48:43 +0000

What do you do with Linux? is the question being asked by howdoyoulinux.com, who is having a video contest describing what you do with Linux. We all the great things you can do with Linux from a hardware firewall/router to a home theatre system. $2,000 and other prizes will go to the winners.

http://howdoyoulinux.com/

How Vaccuum Tubes Are Made and Used, Explained in 1942

admin — Wed, 25 Mar 2009 19:50:13 +0000

This is really cool. Gizmodo has an ariticle with videos from the 40s on how vacume tubes were made. These were put together by hand.

How Vaccuum Tubes Are Made and Used, Explained in 1942