Friday, June 02, 2006
Spam filters slap down emails with erection!
Spam filters are good but occasionally they can block legitimate emails.
Large corporations are employing spam filtration software on their mail servers to stop the many thousands of nuisance advertising and unsolicited emails from arriving in the email boxes of their employees. .
A lot of spam filters base their filtration techniques on a combination words, however, some of the cheaper spam filters often will only look for one word before it scraps the email. In the UK this type of email filter caused a stir when an errant e-mail filter caused Rochdale Council to ignore an objection to a planning application because it contained the word "erection".
A constituent had sent three e-mails outlining his objections to a neighbour's proposed house extension. However, the first two e-mails were automatically blocked by the council's security software, apparently because he described the planned work as an "erection" and by the time his third e-mail arrived, he was informed that permission had already been given for the extension.
So what happened? Well it would seem the council use a word based spam filtering software that did not employ integrated heuristics (meaning it learns about the types of emails its blocking) nor did it use a combination of words to cross check if it should filter it out. The council's IT staff are investigating, and have corrected the filter so e-mails that contain "erection" alongside terms such as "planning application" will no longer be blocked. However, this measure may not be the solution. Many spam filters on email servers actually delete the unwanted email before it even comes into the mail sorting section of the server, this is done to free up system resources on the email server. However, it appears it might be necessary for this council to set their email filters to channel emails containing words that could be used in building and planning that could also appear in spam emails to go to holding folder for it staff to check daily.
This is a timely reminder that we need to check the configuration of our own personal spam filters and occasionally check out what is landing in our junk mail folders.
Original story on ZDNET
Large corporations are employing spam filtration software on their mail servers to stop the many thousands of nuisance advertising and unsolicited emails from arriving in the email boxes of their employees. .
A lot of spam filters base their filtration techniques on a combination words, however, some of the cheaper spam filters often will only look for one word before it scraps the email. In the UK this type of email filter caused a stir when an errant e-mail filter caused Rochdale Council to ignore an objection to a planning application because it contained the word "erection".
A constituent had sent three e-mails outlining his objections to a neighbour's proposed house extension. However, the first two e-mails were automatically blocked by the council's security software, apparently because he described the planned work as an "erection" and by the time his third e-mail arrived, he was informed that permission had already been given for the extension.
So what happened? Well it would seem the council use a word based spam filtering software that did not employ integrated heuristics (meaning it learns about the types of emails its blocking) nor did it use a combination of words to cross check if it should filter it out. The council's IT staff are investigating, and have corrected the filter so e-mails that contain "erection" alongside terms such as "planning application" will no longer be blocked. However, this measure may not be the solution. Many spam filters on email servers actually delete the unwanted email before it even comes into the mail sorting section of the server, this is done to free up system resources on the email server. However, it appears it might be necessary for this council to set their email filters to channel emails containing words that could be used in building and planning that could also appear in spam emails to go to holding folder for it staff to check daily.
This is a timely reminder that we need to check the configuration of our own personal spam filters and occasionally check out what is landing in our junk mail folders.
Original story on ZDNET
# posted by Peter Saville - IT Consultant @ 7:14 PM 
