Make sure you're not unwittingly helping spammers with their crime: Internet ScamBusters #328
On the face of it, spam may seem to just be a big mailbox nuisance. But it's really a much bigger threat.
It can be used to gain access to your PC not only for identity theft but also to suck it into a robot network of "zombie" machines that then spam other PCs.
Usually, victims are totally unaware their computer has been hijacked. In this spam update, we reveal the tell-tale signs and explain what you can do to protect yourself.
Spam Update: How You May Unknowingly Be Contributing to the Spam Problem
To most people, spam is just a darned nuisance. But to others, this insidious stream of electronic junk mail and evil-bearing messages can be anything from a drag on their PC performance to a real threat to their reputation, their identity and even their livelihood.
We've covered the subject in some detail in the past, for example, in this article on how to dramatically reduce the amount of spam you're getting, as well as these 10 tips on how to reduce the amount of spam you receive.
Anti Spam: How to dramatically reduce the amount of spam you're receiving
In this spam update, we'll take a closer look at the scale of the problem and the hidden risk that threatens so many of us -- the chance our own computers are being taken over and used as a spamming tool.
How Big a Problem is Spam?
First, let's get a handle on the current scale and source of spam (which is illegal in the US, by the way).
How many emails would you guess are pumped out from dedicated spam servers and "zombie" PCs (more on these later) every month?
Millions, maybe tens of millions, you might say. Nope. Hundreds of millions? Billions? Tens of billions? Nope, nope, nope. Try hundreds of billions and you'd be getting a little warmer. Go into the trillions and you're about there.
In fact, one botnet -- a "robot network" of home and business PCs hijacked when their users unwittingly download Trojan viruses -- sends out more than 38 billion messages every day (which is more than 400,000 per second). That's more than ONE TRILLION SPAMS a month from one botnet alone. And it's not even the biggest one around!
On average, three out of every four emails we receive -- that's 75% -- are spam.
The proportion can surge to over 95% ahead of special occasions like Valentine's Day, or drop as low as 50% when one of the big spammers gets caught and shut down, as happened last year in California.
Nearly a quarter of all spam come from the US, with China and Brazil in second and third places. Mostly, these messages are peddling rubbish products, like diet and "enhancement" pills, fake designer watches and jewelry.
They're just the "nuisance" spam. But they do their job. Statistics from security firm Symantec show that one in every 12 million yields a sale. Maybe that doesn't sound a lot but, given the size of the spam flood, it works out at several every minute.
Far more worrying is the flood of spam hawking unsavory and downright malicious products and services -- such as links to adult websites or fraudulent "tips" on penny stocks and, worst of all, links or attachments that dump viruses, Trojans and other malware on to your PC.
To deal with these spam emails, we mainly rely on increasingly sophisticated spam "filters" built into email scanning software. But the spammers are clever too and continually come up with new ways to get their messages through.
For those that get through the barriers, it's down to common sense -- the things we regularly talk about here at Scambusters, like ensuring you have up to date security software on your PC and avoiding links and downloads unless you're 110% sure they're OK.
How sure is 110%? Well, we can tell you what it's not. Even if you get an email that seems to be from someone you know, that's not 110%. Spammers can disguise the "From" address line, or may even have hijacked your friend's or relative's email account and sending out messages direct from their mailbox. That's how reputations get ruined.
Botnet Trojans can also invade via invisible computer code on web pages or even via instant messages. And, as statistics show, people ARE clicking on links that upload malware onto their PCs -- programs that do everything from stealing information for identity theft to hijacking them and linking them into a botnet.
By the way, Macs have much less of this problem than PCs. (We always get this question from our Mac subscribers, so we thought we'd answer it directly.)
"Zombie" PCs
These latter ones are the dreaded "zombie" PCs we talked about above. It's hard to say how many computers have been taken over because most people don't know their machines have been compromised.
But we do know that the botnet we mentioned earlier links more than 600,000 machines all over the world. And the biggest botnet has more than 1 million PCs sitting in the home offices, dens, and bedrooms of people like you and us. In all, there may be tens of millions of zombies worldwide.
The bad news is that if your machine is infected in this way, you may unwittingly be a party to criminal activities, which, at least in theory, could make you legally liable for the consequences.
Is Your PC Part of a BotNet?
Obviously, we can't know for sure, but here is a fascinating way of thinking about it: As we mentioned, most people who are infected are unaware of the problem. And unfortunately, reliable statistics are difficult to get (at best).
Nonetheless, we estimate that roughly 5,100 and 21,250 of our Scambusters subscribers are infected with a virus, trojan, malware, spyware or hidden software that makes their PC part of a botnet. Wow!
So, How Can You Tell if Your PC Has Been Hijacked?
Tell-tale signs include:
- A big slowdown in PC performance, including longer times to start up, to shut down and to access the Internet. Even your mouse and keyboard responses may slow down.
- Online pages may also become slow to load, and sometimes your web browser may keep closing down for no apparent reason.
- Your Internet security program is inexplicably switched off and/or access to Internet security websites is blocked.
- Pop-up ads appear even when your browser is closed.
- Frequent hard drive activity is noted even when your machine is not being used.
- Messages arrive in your inbox saying emails you didn't know you'd sent could not be delivered ("bounce" notifications).
It's important to point out that none of these things may necessarily happen if your machine is infected. So NOT having these occur does not mean you're safe.
In other cases, especially a performance slowdown or an over-active hard drive, there can be non-malicious causes, such as a full drive, too many programs running at once or automatic file indexing operations.
But if you think your machine is infected (or even if you don't since the vast majority of people don't realize their PC has been compromised), we recommend you now run a security scan using either your installed software or by running a free online scan such as those offered by McAfee and Symantec. You can also go to Microsoft and download their latest malicious software removal tool.
How to Reduce the Risk
What can you do to eliminate or reduce the risk of being sucked into a botnet in the first place?
Installing Internet security software -- including a firewall -- and ensuring it is always bang up to date is your first line of defense.
There are also one or two dedicated "anti-bot" programs on the market (for example Norton AntiBot) but most Internet security packages will do the job, stopping the viruses from installing in the first place.
If one did get through, regular scans should expose and delete zombie malware.
Strengthen your defense further by instructing the application to ask your permission when programs try to access the Internet. The 'Help' menu in the security software should tell you how to do that.
You might also unplug or otherwise switch off your Internet connection when you don't need to be online.
The trouble is that, as with a lot of malware, if you don't completely eradicate it, it may reinstall. In this case, the only options may be to have it professionally removed or to reformat your hard drive (which, of course, will delete all data along with the malware).
Above all, remember that the biggest risk to your PC becoming infected is you!
Don't click on links or download stuff without thinking very carefully about those risks. Don't visit sites that pose extra risks. And above all, don't respond to spam. Ever!
We'll be back next week with another, lighter issue of Scambusters. See you then!