Routers

Good PC Security Begins With a Baseline

I received some good feedback on my “14 Golden Rules of Computer Security” list, in particular, this comment from Michael: “…you encourage people to go through all the effort of running Virtual Machines to protect themselves from malware, but you don’t actually encourage them to run Anti-Virus software. Which basically, unfortunately, means you’re violating rule #1 and much more likely to run into rule #12.” This lead to a review of past articles I’ve posted on the subject and my finding that though I’ve covered all of the bases, my writing is a bit fragmented. So, you can go back to “Nine Steps to System Security – 2008", “The Lazy Man’s Way to System Security”, and “14 Golden Rules of Computer Security” and put them all together for a complete PC security package, but that’s a lot for the average user to digest.

As of today, I’m embarking on a major pre-release revision of the eBook, 14 Golden Rules of Computer Security to make sure all of the bases are covered in a logical combination and sequence. In essence, the book will begin with the concept of a security baseline—the bare security essentials—for a normal home PC setup and will branch from there.

What’s a good PC security baseline? In “The Lazy Man’s Way to System Security,” I proposed these four bare security essentials: “…a NAT router; a good antivirus program; a good anti-malware program; and, a good software firewall.” That was good enough at the time, but these days antivirus, antimalware and a software firewall are usually combined into a single suite. I choose to align with Windows Secrets’  Security Baseline page: “…a hardware firewall that’s built into your [NAT] router, security software that guards against all types of malware threats, a software-update service to ensure that your applications are patched against the latest exploits, and a secure browser.”

There are many possibilities for implementing those four basic items and that will be well covered in the book.

Worm Targets Home Networking Equipment

As reported yesterday in The Register, the “psyb0t” worm targets home routers and modems and may be the first piece of malware to do so. Researchers from DroneBL, a real-time tracker of abusable IPs, say that as of March 22 100,000 hosts had been infected.

Whether or not your equipment is vulnerable depends on three things:

Your device is a mipsel (MIPS running in little-endian mode, this is what the worm is compiled for) device.

Your device also has telnet, SSH or web-based interfaces available to the WAN, and

Your username and password combinations are weak, OR the daemons that your firmware uses are exploitable.

“This technique is one to be extremely concerned about,” the researchers say, “because most end users will not know their network has been hacked, or that their router is exploited. This means that in the future, this could be an attack vector for the theft of personally identifying information.”

If you believe your equipment is vulnerable or has been compromised, you should immediately take the following actions:

1. Power cycle your router.
2. Disable WAN-facing telnet, SSH or web-based configuration interfaces.
3. Change the passwords to something unguessable (see this article).
4. Upgrade to the latest firmware.

Five Essential Steps to Secure Your Home PCs & Network

When we buy an appliance, we expect to be able to take it home, take a brief glance at the instructions for setting it up, plug it in and go. For most things, this expectation is fulfilled, even, unfortunately, for the home PC. In fact, once you get a few things plugged into the back of it all you have to do is turn it on and start surfing. When you first start a Windows PC, there’s a short setup routine that asks if you want to turn on Automatic Updates (recommended), but little else in the way of how to properly secure your PC and the network it’s plugged into.

PC makers should at least provide a short, animated tutorial or video that explains these five essential steps to securing a home PC and network:

1. Install a NAT router. Inexpensive, and easy to configure, a NAT (Network Address Translation) router is your first line of defense on the Internet. While the Windows firewall is on by default these days, if your PC is plugged directly into your broadband router, you’re visible to everyone on the ‘Net. The router takes this live Internet address and translates it to a private address that is invisible to anyone on the outside.

2. Change the router default password. All routers come pre-configured with a default login and password. These are well known and lists are posted on the Web. Here’s an example of one that’s searchable by router model: http://www.routerpasswords.com/. While an attacker normally can’t get to this from the outside, if you somehow get infected with remote control malware, an attacker can get to it from your computer. He can change the settings to send you virtually anywhere he wants you to go. Not good.

3. Install and/or update a security suite. Most PCs these days come bundled with either anti-virus or a full security suite like McAfee Internet Security, Norton Internet Security or the like. My favorite is ESET Smart Security; unfortunately, this isn’t one that you’ll see bundled with a new PC. Make sure the software is up to date and make sure it will update itself automatically.

4. Turn on Automatic Updates. You should have done this when you set up the computer, but if you haven’t, do it now by following these instructions.

5. Learn about and follow safe computing practices. All of the security devices and software in the world won’t help you if you click on pop-ups, open every email you get, click on random links, and generally practice unsafe surfing. Unfortunately, this is the one of the main reasons why the criminals continue to succeed. Take some time to learn how to be safe on the ‘Net by taking advantage of these free resources:

Nine Steps to System Security - 2008: http://tinyurl.com/6nt2jr
Home Network Security: http://www.us-cert.gov/reading_room/home-network-security/
Recognizing and avoiding email scams: http://www.us-cert.gov/reading_room/emailscams_0905.pdf
Protecting your privacy: http://www.us-cert.gov/cas/tips/ST04-013.html
Avoiding Social Engineering and Phishing Attacks: http://www.us-cert.gov/cas/tips/ST04-014.html

Good luck, and be careful out there.

Software for Secure Computing: Personal Firewalls

How to Secure Your Computer: Maxim #2 stressed the importance of using a NAT router to make your network “invisible” to criminal hackers and other Internet riffraff.  This is excellent protection against inbound malicious connections, but it does nothing to block outbound connections originated on the local network. The router won’t stop back-door trojans, adware, spyware, and the like from “phoning home” with your sensitive information. This behavior is by design; if outbound connections were blocked, you’d never be able to browse the Web. The problem is that if you inadvertently get infected by a mistaken click or a cross-site scripting (XSS) vulnerability, you’re in trouble. You may not even know you’ve been infected–I’ve seen bot-infected machines running up-to-date antivirus software happily spewing spam emails by the thousands.

One of the most important pieces of software for secure computing is a properly configured, proven software firewall. Don’t rely only on Windows XP’s built-in firewall–it blocks inbound attacks only (see Is Microsoft’s Firewall Secure?) and has flaws of its own (see Windows Firewall flaw may hide open ports). While Vista’s firewall does offer outbound filtering, it isn’t much better (see Analysis: New Windows Vista Firewall Fails on Outbound Security for more information).

My favorite personal firewalls for secure computing are the Comodo Personal Firewall (free), and the Sunbelt Kerio Personal Firewall (full-featured for 30 days, then runs free in limited-feature mode, $19.95/yr for full version). I’m currently testing the ESET Smart Security suite and from what I’m seeing, this may be one to recommend to your non-savvy home users; it’s non-intrusive in automatic mode, allowing you to surf freely without those annoying do-you-really-want-to-do-this popups.

The Lazy Man’s Way to System Security

A good many people have responded to my various articles on system security. Most of the feedback has been positive, but many wondered if there might be a simpler approach, some basic things you can do to protect yourself without too much hard work.

You’re in luck. Call it the lazy man’s way to system security; if you install protection against the the three biggest threats to your on-line security–infections by viruses, worms and Trojans, malicious software (spyware, adware, browser hijackers) and crackers who wish to secretly access and control your PC–you’ll be protected from the worst of security problems. One caveat, however: if you go to questionable sites (you know the ones I mean!) and are in the habit of clicking on links in pop-ups and spam emails, you’re out of luck—nothing can help you because you’re inviting infection.

But, for those who generally try to avoid the bad stuff, these are the four bare security essentials: a NAT router; a good antivirus program; a good anti-malware program; and, a good software firewall. Simple, and highly effective for most users.

Before you ask, the answer is yes, you still need a software firewall, even if you already have a NAT router or hardware firewall. Most hardware firewalls are configured to keep bad traffic from getting in, but will let most traffic from your network out, so they don’t keep those sneaky tracking programs from phoning home. A software firewall will at least give you some warning when a program is trying to access the Internet and you can decide whether to allow it. Besides, it gives you an extra layer of protection, just in case.

I highly recommend you read and apply Nine Steps to System Security - 2008, but if you’re feeling a bit lazy today, the four essentials will get you by.

Nine Steps to System Security - 2008

It isn’t getting any better on The Wild, Wild Web, despite state and federal government attempts to arrest and prosecute those responsible for electronically-perpetrated criminal acts. Spyware and malware of all kinds are increasingly more stealthy and difficult to remove thanks to rootkit technology. With the advent of Web 2.0 and its emphasis on sharing and collaboration, web-based attacks are more prevalent than ever, especially those that rely on JavaScript and other scripting languages.

CAN-SPAM did little to deter or eliminate spammers, and today the spam problem is even worse thanks to huge botnets run by organized cyber-crime syndicates. Phishing attacks are harder to detect and more frequent. Recently, I spent the better part of two days cleaning up the aftermath of a mass mailer worm infection for one of our clients; their email is still being blocked by some servers. In its September 2005 issue, Consumer Reports said, “One Third Of Net Users Damaged By Malware.” Considering that article is three years old, I’d wager that the number of infected computers has doubled since then.

In my job as a systems engineer for Connective Computing, Inc., I deal with the effects of malware nearly every day. My previous releases of this article, “Seven Steps to System Security - 2004″ , and “Eight Steps to System Security – 2005“, listed the field-proven steps I recommend to everyone I know. It’s been nearly three years since I published the last guide, but those eight steps haven’t changed much; they just need to be brought up to date, and a new step involving disabling scripting in the browser has been added. Computer users still haven’t learned safe surfing practices, however (will they ever?), and must modify their on-line behavior–particularly by applying the first step–for rest of these steps to be truly effective.

Did I mention these things are proven? They are. These are practices have been protecting computer users in homes and businesses for as long as I’ve been using them. This is free advice that’s really worth something:

1. Repeat after me: I will NEVER, EVER click on any pop-up of any kind - NEVER, EVER. Not even on the “X” (it’s usually safe, but why take the chance?). Use the key combination Alt-F4 instead; it safely closes the current window. In the slimy world of sleaze-ware, “No” means yes, “Cancel” means yes, “Close” means yes - ANY click on a button means yes. So many times users ask, “How did I get that? I clicked ‘no’ when it asked me!” Well, sorry, but you clicked, so they got you. NEVER, EVER CLICK!
2. Although Internet Explorer 7.0 has enhanced security and has been detached somewhat from the Windows operating system, it is still too big a target. Crackers are still writing malware that exploits IE security flaws. I recommend you use Firefox or Opera to browse the Web. (Some web sites still require IE, so you’ll be forced to use it for those, but you should minimize its use otherwise.) Whatever browser you use, be sure you configure your preferences to block all unwanted pop-ups or install a pop-up killer like the Google Tool Bar. And while you’re at it, re-read #1!
3. Patch your system. If you’re still running XP, make sure you have at least service pack 2. If you’re a home user, install service pack 3. (I still see systems that are running XP with service pack 1 or 1a, probably because they turned off automatic updates. While some argue against it, I recommend you turn them on.) And be sure to install any recommended security updates and patches for ALL software on your system, - especially Microsoft Office - not just Windows. If you’re running Windows Vista, you benefit from its enhanced security, but you still need to keep ALL of your applications patched. Secunia’s Online Software Inspector is an excellent tool for scanning your system’s applications to discover those that need updates.
4. Besides installing a NAT router (see How to Secure Your Computer: Maxim #2), run a properly-configured, proven software firewall. Don’t rely only on Windows XP’s built-in firewall - it blocks inbound attacks only (see this article) and it has flaws of its own (see this article). It will not stop back-door trojans, adware, spyware, and the like from “phoning home” with your sensitive information. (See this article for more info.) While Vista’s firewall does offer outbound filtering, it isn’t much better (see this article for more information). My favorites are the Comodo Personal Firewall (free), and the Sunbelt Kerio Personal Firewall (full-featured for 30 days, then runs free in limited-feature mode, $19.95/yr for full version).
5. Run a good anti-virus program. Choices abound. I have used AntiVir Personal Edition (free) and Grisoft’s AVG (free). Other good ones are Avast! and Comodo AntiVirus.
6. Run multiple anti-spyware/anti-adware programs and keep them updated. I recommend: a. Spyware Blaster. This free program blocks adware and spyware from installing in the first place and is frequently updated; b. Ad-Aware. Scan weekly, more frequently if you are a heavy surfer; c. Spybot S&D. Run it on the same schedule as Ad-Aware; d. Microsoft’s Windows Defender is an excellent product and is installed by default in Windows Vista. Configure it for real time protection and automatic updates. One of the best commercial anti-spyware applications is Sunbelt Software’s CounterSpy. It is a PC World Best Buy award winner. Comodo BOClean:AntiMalware is also a good one and it’s free.
7. Run a spam blocker to isolate junk e-mail. Most malware and all phishing attempts rely on spam. You want to isolate this stuff and delete it. NEVER, I repeat, NEVER, EVER click on a link in any e-mail you are not absolutely certain is legitimate. And to be as safe as possible, always type in the address of your bank, credit card companies, and any other site that you want to keep secure. (See #1 above and apply that principle to links, too!) One of the best programs is Open Field Software’s ella for Spam Control. It uses wizards to “train” it to your personal specifications. There are free and paid versions that work with Outlook, Outlook Express. My clients swear by it. Another good program is Sunbelt Software’s iHate Spam.
8. On Windows XP, set up a restricted user account and use that for routine tasks. Only log on with administrative privileges when you need to install or configure software. This will prevent rogue programs from affecting your system - they won’t be able to install. You can activate the “run as” feature so you can do administrative tasks while logged in as a restricted user. Microsoft Knowledge Base article Q294676 explains how to activate and use this feature. If you are running Vista, you don’t have to worry about this step: User Access Control (UAC) takes care of it.
9. Finally, disable scripting in your browser. If you use IE (you probably shouldn’t, see Step 2), Tony Bradley gives you an excellent step-by-step procedure to accomplish this. Firefox users have a more elegant solution in the form of an add-on: NoScript. I use it on every PC. Scripts are blocked globally by default, but you can selectively activate them if you trust the site. For example, you can trust the main site’s scripts but keep blocking any advertising or other third party scripts with no ill effects.

While total immunity is impossible - new infections and variations on existing exploits appear daily - these nine steps will help prevent, catch, or clean 98 percent of the junkware out there. As for the other two percent - or if you are already badly infected - you’ll need to hire a geek like me.

Sure-fire Spam Zombie Killer

The other day, I got a call from one of my clients who said that their email was bouncing back from people they had always been able to send to. I investigated and found that the error message was to the effect of <hostname.domain #5.5.0 smtp;550 Blocked;Spam/Zombie address listed at spamhaus.org sbl-xbl>.

Well, that was odd, because the client is running a bona fide Exchange server and a check of the server revealed nothing wrong that I could see. Thinking that maybe an employee was infected with a mass-mailer trojan, I blocked all traffic on smtp port 25 from all addresses on the network except the Exchange server.

Running the netstat -an command on my client’s PC revealed 88 connections, all trying to send mail out on port 25, which the firewall was now blocking.

Certainly, you don’t want to get infected by a mass-mailer trojan, but blocking outbound traffic on port 25 from your network is a sure-fire spam zombie killer and will prevent your IP address from getting blacklisted if someone does get infected.Of course, you’ll want to clean up that infection as quickly as possible.

Unpatched PC “0wn3d” in Four Minutes or 16 Hours; Which is it?

I just love stories like this one. On the one hand, Internet Storm Center researchers say an unpatched PC connected to the Internet will be compromised in less than four minutes. On the other hand, a researcher and co-founder of the German Honeypot Project (GHP), Thorsten Holz, claims the survival time is much higher than 4 minutes and in fact is nearer 16 hours. “Compared to the survival time from the Internet Storm Center [ISC] which is currently below five minutes, we measure a higher survival time,” he said in a post to the project’s blog. The blog has some interesting graphs, one of which shows that survival time is just under 1000 minutes, or about 16 hours.

So, which is it? Do we believe ISC or GHP? I can tell you from experience with my own firewall logs that my IP address is probed for common vulnerabilities about every two minutes, sometimes as often as once per minute. Based on this, I’d be inclined to believe ISC’s estimate. The bottom line is it doesn’t really matter who’s right–we all agree that it’s a bad idea to connect an unpatched PC to the Internet. From the ISC diary:

While the survival time measured varies quite a bit across methods used, pretty much all agree that placing an unpatched Windows computer directly onto the Internet in the hope that it downloads the patches faster than it gets exploited are odds that you wouldn’t bet on in Vegas.  Using a NAT router and a correctly configured personal firewall is the way to go - both these measures help a lot to improve the odds in favor or your PC.

Be careful out there.

Ken is a Systems Engineer at Connective Computing, Inc. specializing in network and desktop security for small and medium businesses. Ken helps others through his Ask the Geek blog, is a regular contributor to Dave’s Computer Tips newsletter, and is currently working on his first consumer-oriented book on computer security.

This Router Configuration Option Can Be Dangerous

In my February 20th post, “Omit This Setup Step and Your Router Can Be Easily Compromised,” I stressed the importance of changing the default router password. I forgot to mention in that article another configuration option that can be dangerous, even if you’ve changed the default password: Remote management. While I’ve never seen this feature enabled by default, it’s better to err on the side of paranoia and make certain it isn’t enabled on your router.

Obviously, this would be a serious problem if you haven’t changed the default password; it’s less of a concern if you have, but passwords can be cracked and if someone decides to target you, it’s not a good idea to have your router’s login visible to them. If you absolutely must have remote management available to you (why?), then it’s imperative that when you change the default login password, you use an unguessable and virtually uncrackable one.

Are You a Hacker Target?

Aside from those unenlightened, naive souls who invite every hacker, phisher and Nigerian scammer on the planet into their computers how many people actually fall victim to hackers? I’m talking about people who take reasonable precautions, like installing a NAT router, running a personal firewall (not Windows’ firewall) and anti-virus software. I ask this question because for some months now, I’ve been running half naked behind my hardware firewall: no anti-virus, no software firewall, just a hosts file to block known bad sites (I do update it frequently). I use both IE and Firefox for web surfing.

I haven’t been hacked, nor have I been infected by any malware. In my entire history of computing (since 1974), I’ve never been plagued by a virus or worm. I guarantee you that my PCs are not part of any botnet. No one has ever tried to run a DDOS attack on me. It’s not that I’m invisible–Google my name and you’ll get several thousand hits (some of those aren’t me; apparently more than one Ken Harthun out there). I have a couple of different web sites in plain view, too.

Am I immune to attack or just lucky? Or is it that by applying the various security tips I give you here (yes, I do the same things I tell you to do) , I’m out smarting the hackers so they can’t figure out how to get me? Food for thought. Your comments are welcome.