[Mimedefang] javascript in address header

Joseph Brennan brennan at columbia.edu
Wed Mar 20 15:51:45 EDT 2013


Ever see one of these?--

To: Joe B <jb51 at columbia.edu<javascript:_e({}, 
'cvml','jb51 at columbia.edu');>>

I changed the name and address, but otherwise this is what someone on Gmail 
sent to a user here. The envelope RCPT was evidently normal, as logged by 
sendmail, but when we re-sent it to an Exchange system (still with a normal 
RCPT), Exchange rejected the header.

This 
<http://stackoverflow.com/questions/14662296/javascript-cvml-in-an-email-address> 
gives a too-brief explanation of what it is.

It wouldn't be hard to remove with MimeDefang. I cannot find an example in 
my own voluminous mail from Gmail users, which has me wondering how rare it 
is. I wonder whether any email client would run javascript in a header line 
anyway. I'm considering writing it off as one weird case.

Joseph Brennan
Columbia University Information Technology





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