Five important security apps for Linux, Mac OS X and Windows

A little bit of common sense goes a long way when it comes to keeping your system safe and locked down. But some of us have friends, family, and coworkers that need a little bit more. Ars has five freeware or shareware security apps for Windows, Mac OS X, and Linux that will go a long way towards keeping your systems secure.

Introduction

No matter what OS you use, you need to think about security. But what happens when you don't have time to think? Turn to Ars!

We've got you covered with five freeware or shareware security tools for Linux boxes, Macs, and Windows machines, all recommended by Ars staffers. Running behind a firewall and a NAT router can keep many threats at bay, and skeptical computing can keep most people safe on the Internet, but it never hurts to have a toolbox of well-crafted apps that you can reach into should your machine be breached.

Windows

A quick note on security suites: we don't believe in them. There is no security suite out there that properly takes care of two or more security needs; a company usually gets good at one aspect and wants to expand into another for the sake of growing their business. We have not yet encountered a truly solid security suite, although some companies are slowly getting there.

The idea here is to keep expenditures down to a minimum while still addressing the top five security software categories (in no particular order) for a Windows PC.

Firewall

Almost everyone has sensitive data on their hard drives that they prefer to keep off the network. For Windows XP, the Windows Firewall is not good enough. We recommend using Comodo Firewall Pro Free instead. First introduced as a part of Service Pack 2, XP's firewall is not capable of blocking outbound connections. This is the number one reason for using a software firewall, as a router (also known as a hardware firewall) takes care of inbound connections perfectly.

For Windows Vista, Microsoft addressed this problem; spyware and viruses that "phoned home" with stolen information would be caught by Vista's firewall. If you have Windows Vista, there is no need for Comodo or any third-party firewall. Regardless of whether you're on XP or Vista, a router is essential. We would even go as far as saying that a hardware firewall is more important than having a software firewall enabled—regardless of which OS you're running.

Recommendations

• Windows Vista: built-in firewall
• Windows XP: Comodo Firewall Free Pro (freeware)

Anti-virus

This is the security application most users shouldn't pass up. If you insist on not shelling out a dime, we recommend one of the three As: Antivir, Avast, or AVG. The choice between the three comes down to user preference: download and install them one by one (never, under any circumstances, have more than one anti-virus program installed on your computer) and check out which features and interface suits you best. Make sure to compare how often updates are sent out, how well the application can auto-update itself, and the resource footprint it has on your computer.

For commercial anti-virus software, the choice comes down to two recommendations: ESET NOD32 or Kaspersky Anti-Virus. Kaspersky Anti-Virus has slightly superior detection rates based on signature files, while NOD32 provides excellent heuristic detection (called "ThreatSense" by ESET) for new viruses discovered in the wild. Either is an excellent anti-virus solution.

Recommendations

• Freeware: Antivir or Avast or AVG
• Shareware: ESET NOD32 or KasperSky Antivirus

Anti-spyware and Anti-adware

While Spybot Search & Destroy was king in anti-spyware for a long while, this is no longer the case. Thanks to Microsoft's acquisition of GIANT Company Software in December 2004, the software maker now has an anti-spyware offering available for Windows XP and that comes with Windows Vista.

Windows Defender, while a very solid application considering its young age, may be better than Spybot but it is still not quite there yet. Lavasoft Ad-Aware Free is the freeware application we recommend, but we do not suggest disabling Windows Defender; use them together. On the other hand, if you do have the cash, there is no question that the best commercial option out there is Webroot Spy Sweeper.

Recommendation

• Freeware: Lavasoft Add-Aware Free and Windows Defender
• Shareware: Webroot Spy Sweeper

Encryption

Everyone has those files on their computer that are only for their eyes. Password-protection is a possibility, but passwords can be cracked too easily in this day and age. Give a 13-year-old the right program, and weep as he breaks into your p0rn stash and locks you out of it. For all your privacy needs, encryption is the way to go. TrueCrypt is an application that offers on-the-fly encryption with minimal user intervention. It is the best that is out there right now, and it's entirely free. Furthermore, TrueCrypt is available for Microsoft Windows, Mac OS X, and Linux.

Recommendation

• Freeware: TrueCrypt

Watchdog

This is the application that was designed to annoy you. If used correctly, it can block various types of malware from getting onto your computer. It monitors what you or an application is trying to change on your computer, and informs you when it deems something might be being changed that shouldn't be. Unfortunately, this occurs more often under legitimate changes than under non-legitimate ones. For this reason, users often choose to disable or not to install such programs. For Windows Vista, the watchdog of choice is none other than the unloved User Account Control (UAC), and for Windows XP, we recommend Winpatrol. Watchdog programs can be—but are not recommended to be—used as alternatives to other security solutions.

Recommendation

• Windows Vista: UAC
• Windows XP: Winpatrol

Software Raid

1. Create device:

root@host:/# mknod /dev/md0 b 9 0  root@host:/# mknod /dev/md1 b 9 1  [...] 

2. Create partitions:

root@host:/# fdisk /dev/sda  root@host:/# fdisk /dev/sdb  

3. Create filesystem:

root@host:/# mkreiserfs /dev/sda1  root@host:/# mkreiserfs /dev/sdb1  [...] 

4. Cretate RAID:

root@host:/# mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1 root@host:/# mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2 [...] 

Crontab

How to edit crontab with favourite editor..

root@host:/# export VISUAL="nano -w"  

Samba

Connect to a samba share on another computer...

root@host:/# smbmount //192.168.78.5/share /local/share -o rw,username=piggy,password=XXXXXXXX 

Connect to a domain...

root@host:/# net rpc join MEMBER -S server -U user%password 

Linux Kernel

Patching

root@host:/# cd /usr/src/linux root@host:/# patch -p1 

Basic commands

Q: How do I remove or access a file that has a filename that begins with special characters?
A: Use ./ before the filename

root@host:/# rm ./--bad-filename 

Q: How do I use find to locate files and run a command on the found files?
A: Use the the -exec '{}' \; parameters:

find ./ -name "*.$$$" -exec chmod +w '{}' \; 

LILO

Q: I get this LILO warning when booting up: "Error: Duplicated Volume Id"
A: Run lilo and clear the volume serial number on the boot device

root@host:/# lilo -z -M /dev/hda 

Swapfile - not swap partition - in Linux 2.6.x

Q: How do you create and use a swapfile in Linux 2.6?
A: Well look below, make the swapfile as big as the internal memory.

root@host:/# dd if=/dev/zero of=/swapfile bs=1M count=256 root@host:/# mkswap /swapfile  Edit /etc/fstab, add: /swapfile  none   swap   defaults  0 0  root@host:/# swapon -a  Be sure to mount the swapfile after regular file systems is mounted (in your startup scripts): /bin/mount -n -o remount,rw /bin/rm -f /etc/mtab* /bin/mount -a -O no_netdev swapon -a 

No pxe boot after doing a warm boot

Q: Why doesn't my computer (Soekris, EPIA box) boot via PXE after a warm reboot?
A: Apparently a problem with Linux/Wake On Lan. Get ethtool and run this command in a startup or shutdown script:

ethtool -s eth0 wol d 

Count unique rows in httpd access file

grep sakerhetsbesiktning/index2.html assa.access |sed 's/\([0-9.]*\).*/\1/g'|sort|uniq|wc -l 

Convert several images in a folder

for img in `ls *.JPG` ; do for> convert $img -resize 640x480 thumb-$img for> done 

Find large folders

du -h | egrep -e [0-9\.]+G 

SSH without login