Testing

Jakob Bohm jb-openssl at wisemo.com
Thu Sep 3 10:18:24 UTC 2020


On 2020-09-03 09:42, Marc Roos wrote:
> 
> PTR record, SPF, DKIM and DMARC are also set by spammers, and sometimes
> even just before a spam run. It is either choosing to do amazons work or
> not having any work. If more and more are blocking the amazon cloud it
> would make their clients leave and this finally migth have them spend
> more on their abuse department.
> 
> 

For your information, AWS apparently blocks TCP port 25 unless the
customer (not someone hacking an AWS instance) explicitly requests a
custom PTR record using a form where the customer promises not to Spam.
Custom PTR records don't look like
ec2-184-72-79-140.compute-1.amazonaws.com .

I am unsure how Richard's example that obviously tricked a server to
send a HTTP request to the OpenSSL mail server got past the port 25
block (this appears to be a common form of server side request forgery).


> 
> 
> -----Original Message-----
> To: openssl-users at openssl.org
> Subject: Re: Testing
> 
> On 2020-08-31 16:28, Marc Roos wrote:
>> Why don't you block the whole compute cloud of amazon?
>> ec2-3-21-30-127.us-east-2.compute.amazonaws.com
> Please note, that at least our company hosts a secondary MX in the EC2
> cloud, with the option to direct my posts to the list through that
> server.  However proper PTR record, SPF, DKIM and DMARC checks should
> all pass for such posts.
> 
> Thus rather than blindly blacklisting the Amazon hosting service, maybe
> make the OpenSSL mail server check those things to catch erroneous
> transmissions from web servers.
> 
> 
>>
>> -----Original Message-----
>>
>> To: openssl-users at openssl.org
>> Subject: Testing
>>
>>
>>
>> --
>> -----BEGIN EMAIL SIGNATURE-----
>>
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>>
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>>
>> Link:
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>> .html
>>
>> **********************************************************************
>> **
>> ********************
>>
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>>
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>>
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>>
>> [3] https://www.scribd.com/user/270125049/Teo-En-Ming
>>
>> -----END EMAIL SIGNATURE-----
>>
>>
> 
> 
> 



Enjoy

Jakob
-- 
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
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