Spam rate is exploding
Posted on December 6, 2006
Filed Under Internet, Security |
Spam rate is exploding
If you’ve been anywhere near a computer in the last 6 months, you may have noticed that the amount of spam arriving in email inboxes has exploded. Spammers have again found ways to peddle prescription drugs, male enhancement merchandise, and penny stocks, right under the nose of your favourite spam filter.
Much of this new breed of spam uses images rather than text to get their message out. By putting the written message into an image rather than the body of the email itself, spam filters are unable to read it and will often forward the message as legitimate email.
And when the filters began using Optical Character Recognition (OCR) to read the message embedded in the image, the spammers got around that too. By adding polka dots and other colourful embellishments to the images, the spammers could confuse the OCR process and prevent their messages from being tagged as spam.
Add to the mix some real text below the image that would easily pass a spam test and you can see how determined spammers really are.
An early technique used to block multiple copies of spam by identifying it’s “footprint” has also been thwarted. By using software to change a few pixels of an image, a spammer can make a message appear unique and prevent the message from being identified.
Blocking the address of a spammer is for all intents and purposes ineffective as well. To make spam more difficult to trace and even more difficult to prevent, spammers are using “bots” to send spam from computers all over the planet.
Bots infect a computer in the same way as a Trojan Horse or spyware does. Once infected, the computer becomes a part of a “botnet” and can be used to send spam, more bots, or launch denial of service attacks.
According to www.infoworld.com “Trend identified more than 250,000 new bots each day for the two days after an exploit was developed for the Server Service hole, which Microsoft patched with MS06-040. Typically, the company might identify 250,000 new bots over the course of a month.”
So how bad is it? Strangely enough, the beginning of 2006 was relatively quiet for spam. Today the situation is much worse. According to Ironport, a spam-filtering firm, spam now accounts for more than nine of every ten e-mail messages and spam volume has doubled since last year. Image spam accounts for 25 to 45 percent of all spam.
While there is no bulletproof way to eliminate spam, it is always a good idea to keep your spam filter, antivirus, and antispyware up to date. More on spam can be found at http://www.bowesit.com/blog/2006/03/01/spam-can-be-minimized/
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