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Posted to users@spamassassin.apache.org by Alex <my...@gmail.com> on 2017/09/18 18:58:49 UTC

Legitimate dropbox accounts used for malware

Hi,
I've whitelisted dropbox so I can use some aggressive rules to block
phishing attacks involving dropbox. The problem I'm now having is
legitimate dropbox accounts are being used to send malware with links
to dropbox accounts to download these malicious files.

https://pastebin.com/raw/PFpJeYDX

This email likely would have been tagged if it wasn't for being
whitelisted by SPF. The language in the body is clearly spam.

Does anyone have any recommendations on how to handle this? I found
this because two of my users reported it. We can report it to dropbox,
but that's after the fact.

Re: Legitimate dropbox accounts used for malware

Posted by David Jones <dj...@ena.com>.
On 09/18/2017 01:58 PM, Alex wrote:
> Hi,
> I've whitelisted dropbox so I can use some aggressive rules to block
> phishing attacks involving dropbox. The problem I'm now having is
> legitimate dropbox accounts are being used to send malware with links
> to dropbox accounts to download these malicious files.
> 
> https://pastebin.com/raw/PFpJeYDX
> 
> This email likely would have been tagged if it wasn't for being
> whitelisted by SPF. The language in the body is clearly spam.
> 
> Does anyone have any recommendations on how to handle this? I found
> this because two of my users reported it. We can report it to dropbox,
> but that's after the fact.
> 

Report it to abuse@amazonaws.com and SpamCop which will also report it 
to the same Amazon abuse.

Google for "Amazon abuse" and "dropbox abuse".  Dropbox has an abuse 
reporting process page.

-- 
David Jones

Re: Legitimate dropbox accounts used for malware

Posted by John Hardin <jh...@impsec.org>.
On Mon, 18 Sep 2017, Alex wrote:

> Hi,
> I've whitelisted dropbox so I can use some aggressive rules to block
> phishing attacks involving dropbox. The problem I'm now having is
> legitimate dropbox accounts are being used to send malware with links
> to dropbox accounts to download these malicious files.
>
> https://pastebin.com/raw/PFpJeYDX
>
> This email likely would have been tagged if it wasn't for being
> whitelisted by SPF. The language in the body is clearly spam.
>
> Does anyone have any recommendations on how to handle this? I found
> this because two of my users reported it. We can report it to dropbox,
> but that's after the fact.

Don't whitelist dropbox as a whole. Whitelist specific real dropbox users 
if you must to get them past SA, on explicit request. This of course 
depends on the size of your userbase.

Alternatively, write a meta to offset *most* of the negative points from 
the whitelisting, so that the rest of the rules do still have some chance 
of having an effect.

-- 
  John Hardin KA7OHZ                    http://www.impsec.org/~jhardin/
  jhardin@impsec.org    FALaholic #11174     pgpk -a jhardin@impsec.org
  key: 0xB8732E79 -- 2D8C 34F4 6411 F507 136C  AF76 D822 E6E6 B873 2E79
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