Hi Thomas,
I’ve run the message through the analyser and although a great feature to have
it is not going to catch these emails.
None of the addresses are actually @domain.tld
The Reply-to: is @domain.tld-1.me so the extra -1.me bypasses the spoofing
check.
The DoNoFrom: option is catching the multiple from headers which is great.
All the best,
Colin.
From: Thomas Eckardt [mailto:thomas.ecka...@thockar.com]
Sent: 20 April 2018 15:24
To: ASSP development mailing list <assp-test@lists.sourceforge.net>
Subject: Re: [Assp-test] Multiple From headers/regex based on localdomains
Colin,
solved build 18107 the problem for you?
changed:
...
'DoNoSpoofing4From','Do NoSpoofing for from:'
'Do the NoSpoofing check also for header 'from:', 'sender:', 'reply-to:' and
'errors-to:' addresses.
Thomas
Von: "cw" <colin.war...@gmail.com<mailto:colin.war...@gmail.com>>
An: "ASSP development mailing list"
<Assp-test@lists.sourceforge.net<mailto:Assp-test@lists.sourceforge.net>>
Datum: 14.04.2018 09:47
Betreff: Re: [Assp-test] Multiple From headers/regex based on
localdomains
________________________________
Hi Thomas,
Looks like a good feature. I'll have to double check the headers for this
message. I think the domains in all three from headers actually exist but have
no relation to the recipient.
As the smtp address & from headers are a legitimate but compromised account the
only header that would fail a legitimate domain check would be the reply to
header.
These are carefully crafted phishing emails that are targeted, I've seen them
sent to many accounts departments pretending to be from company directors
requesting bank payments of up to £10,000. Of course the accounts department
goes straight to said director who comes to us wanting to know why we aren't
blocking them.
All the best,
Colin
On Sat, 14 Apr 2018, 08:26 Thomas Eckardt,
<thomas.ecka...@thockar.com<mailto:thomas.ecka...@thockar.com>> wrote:
> I thought this would not be caught by nospoofing because that would only
> match if the RHS ended in the entry from localdomains.
OK.
And what if the 'DoNoFrom' feature would work like this:
Check for Existing and Valid From: and Sender: Header Tag and Address (DoNoFrom)
If enabled, the MIME header is checked for valid From: and Sender: header tags.
This header check fails and faults are counted, if both headers (From: and
Sender:) are missing - or if any of these headers contains not a valid email
address - or if multiple of the same headers are found.
The scoring value nofromValencePB is added for each detected fault.
In your example:
Reply-to: Sender Name
<n...@recipientdomain.tld-1.me<mailto:n...@recipientdomain.tld-1.me>>
To: recipi...@recipientdomain.tld<mailto:recipi...@recipientdomain.tld>
From: Sender Name <f...@domain.tld<mailto:f...@domain.tld>>
From: Sender Name <f...@domain2.tld<mailto:f...@domain2.tld>>
From: Sender Name
<actualsmtpfromaddr...@legitimatebutcompromiseddomain.tld<mailto:actualsmtpfromaddr...@legitimatebutcompromiseddomain.tld>>
'nofromValencePB' would be added two times - one time for each additionally
From: header.
Thomas
Von: "Colin Waring"
<co...@dolphinict.co.uk<mailto:co...@dolphinict.co.uk>>
An: "ASSP development mailing list"
<assp-test@lists.sourceforge.net<mailto:assp-test@lists.sourceforge.net>>
Datum: 13.04.2018 20:55
Betreff: Re: [Assp-test] Multiple From headers/regex based on
localdomains
________________________________
Thank you for the reply Thomas,
Being able to include sender:, reply to: and errors-to: would be handy in my
opinion
However, in this case the local domain was not in any of the from: fields
whatsoever. By using
n...@recipientdomain.tld-1.me<mailto:n...@recipientdomain.tld-1.me>, this hits
a stupid bug in Outlook where in some places it will only display
n...@recipientdomain.tld<mailto:n...@recipientdomain.tld>. The
-1.me<http://1.me/> is completely fictional and varies from message to message.
I thought this would not be caught by nospoofing because that would only match
if the RHS ended in the entry from localdomains.
All the best,
Colin.
From: Thomas Eckardt
<thomas.ecka...@thockar.com<mailto:thomas.ecka...@thockar.com>>
Sent: 13 April 2018 16:55
To: ASSP development mailing list
<assp-test@lists.sourceforge.net<mailto:assp-test@lists.sourceforge.net>>
Subject: Re: [Assp-test] Multiple From headers/regex based on localdomains
Colin,
'DoNoSpoofing4From' should do it - but it is'nt. Only the first 'From:' address
is currently checked and this will not prevent this attack.
But it is possible to include 'sender: , reply-to: and errors-to:' in to this
check - which would catch this mails.
What do you think?
Thomas
Von: "Colin Waring"
<co...@dolphinict.co.uk<mailto:co...@dolphinict.co.uk>>
An: "ASSP development mailing list"
<assp-test@lists.sourceforge.net<mailto:assp-test@lists.sourceforge.net>>
Datum: 13.04.2018 17:17
Betreff: [Assp-test] Multiple From headers/regex based on localdomains
________________________________
Hi,
I’ve a couple of fun ones at the moment. Basically I’m getting reports of
phishing emails that get past everything.
The headers are like this:
Reply-to: Sender Name
<n...@recipientdomain.tld-1.me<mailto:n...@recipientdomain.tld-1.me>>
To: recipi...@recipientdomain.tld<mailto:recipi...@recipientdomain.tld>
From: Sender Name <f...@domain.tld<mailto:f...@domain.tld>>
From: Sender Name <f...@domain2.tld<mailto:f...@domain2.tld>>
From: Sender Name
<actualsmtpfromaddr...@legitimatebutcompromiseddomain.tld<mailto:actualsmtpfromaddr...@legitimatebutcompromiseddomain.tld>>
These bypass no spoofing as none of the from/SMTP header domains are actually
the recipient domain. Annoyingly, Outlook chooses the Reply-to address to
display so it appears almost legitimate.
I’m aware that the RFCs allow multiple from headers, though I can’t see of any
legitimate reason for this so I was considering blocking or increasing spam
score based on this – is this possible with ASSP at the moment or not?
The second thing I was looking at doing was coming up with a regex.
Essentially, all recipient domains are in localdomains.txt so I’d want a regex
that would take all lines from localdomains. If the reply to or smtp from
address is a line from localdomains with anything else after it, then bin it. I
accept that there may in some extremely obscure cases be a clash with a
legitimate domain but do not believe that to be likely. I’ll have a look next
week as to if I can figure out a way to do it but if there’s something obvious
that you could let me know that’d be great.
All the best,
Colin.
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