Ignoring invisible characters in RegEx

Question

I've run into a bit of a conundrum.

I am currently trying to build a regex to filter out some particularly nasty scam emails. I'm sure you've seen them before, using a data dump from a compromised website to threaten to reveal intimate videos.

That's all well and good, except I noticed while testing the regex that some of these messages insert special invisible characters in the middle of words. Like you might see here (I've found it especially hard to find a place that keeps these special characters): Regexr link

I find myself looking for a way to create a regex that might ignore these characters all together, as some emails have them and some don't. In the end, I'm trying to create a match with something like

/all (.*)your contacts

I suggest you start by replacing all 'non word' character with an empty string, then you will have 'normal' Words to search for spam Words. The regex to replace should simply be: '\W+'. — Poul Bak
– Poul Bak, Commented Oct 22, 2018 at 19:17

jmcgriz · Accepted Answer · 2018-10-22 20:23:51Z

1

If there's a particular string you're trying to flag, you could do something like this:

Detect "email" with optional invis characters: /e[^\w]?m[^\w]?a[^\w]?i[^\w]?l/

[^\w]? will detect anything that's not a letter or digit. You could also use [^\w]* if you're seeing more than one invisible character being used between letters.

answered Oct 22, 2018 at 20:23

jmcgriz

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user557597 · Accepted Answer · 2018-10-22 21:42:54Z

0

Most invisible characters are just whitespace.
These don't matter which character set they're rendered in,
it's probably invisible.

If using a Unicode aware regex engine, you could probably just stick
in the whitespace class between the characters you're looking for.

If not, you could try using the class equivalent [ ].

\s =

 [\x{9}-\x{D}\x{1C}-\x{20}\x{85}\x{A0}\x{1680}\x{2000}-\x{200A}\x{2028}-\x{2029}\x{202F}\x{205F}\x{3000}]

Same, but without CRLF's
[^\S\r\n] =

[\x{9}\x{B}-\x{C}\x{1C}-\x{20}\x{85}\x{A0}\x{1680}\x{2000}-\x{200A}\x{2028}-\x{2029}\x{202F}\x{205F}\x{3000}]

answered Oct 22, 2018 at 21:42

user557597

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