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Need better understanding of the use of Regex in spam filters

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  • Last reply by Thomas

Thomas
Thomas
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I have had mixed results with Thunderbird's spam filters. First, even though I have a Personal Address book filter as follows: From -> is in my address book -> Personal Address Book 

  Set Junk Status to -> Not Junk
  Move Message to -> Inbox
  Stop Filter Execution

at the top of my filter list, some items get set to the spam folder anyway. Not sure why this happens.

But the problem I am writing about today is spammers who will modify their subject headers to penetrate simple filters, as follows: Subject -> contains -> Re: Take Advantage of this Offer 

  Delete Message

The spammer is beating my filter by munging the wording, for example TakeAdvantage-of-this, Offer

So I tried changing it to: Subject Regex Match -> matches -> Take[:print:]*Advantage[:print:]*of[:print:]*this[:print:]*Offer 

  <also tried>

Subject Regex Match -> matches -> Take.*Advantage.*of.*this.*Offer

but neither seems to work. If Vanna is available, I'd like to buy a clue.

I have had mixed results with Thunderbird's spam filters. First, even though I have a Personal Address book filter as follows: From -> is in my address book -> Personal Address Book Set Junk Status to -> Not Junk Move Message to -> Inbox Stop Filter Execution at the top of my filter list, some items get set to the spam folder anyway. Not sure why this happens. But the problem I am writing about today is spammers who will modify their subject headers to penetrate simple filters, as follows: Subject -> contains -> Re: Take Advantage of this Offer Delete Message The spammer is beating my filter by munging the wording, for example TakeAdvantage-of-this, Offer So I tried changing it to: Subject Regex Match -> matches -> Take[:print:]*Advantage[:print:]*of[:print:]*this[:print:]*Offer <also tried> Subject Regex Match -> matches -> Take.*Advantage.*of.*this.*Offer but neither seems to work. If Vanna is available, I'd like to buy a clue.

Chosen solution

Lets back up to the beginning.

If you are using IMAP, then some mail is most likely placed as SPAM using server side filtering This is especially so for those using Yahoo based products as they have no way to opt out of their spam filtering on your behalf.

Then we have regex. That is a feature supplied by the Filtaquilla add-on https://addons.thunderbird.net/en-US/thunderbird/addon/filtaquilla/ and as such is not something supported from here. Regular expressions (regex) are a powerful coding tool for searching and matching text to a pattern, but the learning curve is fairly steep. It is not one I have chosen to climb. I suggest you try something like a google search on "regex match" or a site like this https://www.regular-expressions.info/quickstart.html If you are new to regex searching it will take a while. This is not quite wildcards as you might expect.

The hope page for the addon https://quickfilters.quickfolders.org/filtaquilla.html indicates that "Since this code is done using Mozilla javascript, regular expressions should use the Mozilla regex syntax" it also points to the MDN site for reference to regex and to reges101.com to test your regex.

Home that is enough breadcrumbs. .

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Matt
Matt
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  • Top 10 Contributor
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Chosen Solution

Lets back up to the beginning.

If you are using IMAP, then some mail is most likely placed as SPAM using server side filtering This is especially so for those using Yahoo based products as they have no way to opt out of their spam filtering on your behalf.

Then we have regex. That is a feature supplied by the Filtaquilla add-on https://addons.thunderbird.net/en-US/thunderbird/addon/filtaquilla/ and as such is not something supported from here. Regular expressions (regex) are a powerful coding tool for searching and matching text to a pattern, but the learning curve is fairly steep. It is not one I have chosen to climb. I suggest you try something like a google search on "regex match" or a site like this https://www.regular-expressions.info/quickstart.html If you are new to regex searching it will take a while. This is not quite wildcards as you might expect.

The hope page for the addon https://quickfilters.quickfolders.org/filtaquilla.html indicates that "Since this code is done using Mozilla javascript, regular expressions should use the Mozilla regex syntax" it also points to the MDN site for reference to regex and to reges101.com to test your regex.

Home that is enough breadcrumbs. .

Modified by Matt

Thomas
Thomas Question owner
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Thanks, Matt, that is more than enough breadcrumbs. I don't remember installing filtaquilla, but it's possible I was testing quickfilters, forgot about it, and it morphed into filtaquilla. (Website seems to be for both, which itself is confusing.)

Hotmail is the one I have been having trouble with. I wouldn't have bet Micro$oft's spam filtering was effective.

I'm quite experienced with regex, using it with PERL for many years. That was what had me confused. The expressions I tested should have been present in any implementation of regex. Surprised me when they had no effect.

More research needed. Thanks for the breadcrumbs.

Modified by Thomas