Topics

moderated Virus scanning


 

Hi All,

I've been testing virus/phishing scanning the last few weeks and I'm pretty confident that it's catching what it should. In testing, it's scanning all emails, all uploaded files and photos. And right now, if the sender is not a subscriber, it drops any emails it finds has a virus or phishing attack. 

My default implementation would be to turn it on so that it blocks all emails, files and photos that it finds has a virus or phishing attempt. Do you see any reason to not do it this way?

The scanner I'm using is here: http://www.clamav.net/


Thanks,
Mark


 

Hi Mark,

if the sender is not
a subscriber, it drops any emails it finds has a virus or phishing attack.
If the sender is a subscriber then please moderate the message instead of dropping it. False positives are possible.

--
Lena


Chris V
 

Mark

the only question I have is will group owners know what emails are rejected?

Otherwise sounds good to me

Chris

On 21/08/2018 04:24, Mark Fletcher wrote:
Hi All,

I've been testing virus/phishing scanning the last few weeks and I'm pretty confident that it's catching what it should. In testing, it's scanning all emails, all uploaded files and photos. And right now, if the sender is not a subscriber, it drops any emails it finds has a virus or phishing attack.

My default implementation would be to turn it on so that it blocks all emails, files and photos that it finds has a virus or phishing attempt. Do you see any reason to not do it this way?

The scanner I'm using is here: http://www.clamav.net/


Thanks,
Mark


 

On 21 Aug 2018, at 07:03, Lena <Lena@...> wrote:

If the sender is a subscriber then please moderate the message instead of dropping it. False positives are possible.

That seems sensible to me.

best

Nick
___

dUNMUR | member of the AOP


Dave Sergeant
 

I have mixed feelings on this. Will it be possible to disable the virus
scanning on individual groups. Yahoogroups had virus scanning (probably
a far inferior system to what you are proposing) and we always disabled
it. Apart from the odd occasion when members had their Yahoo emails
hacked we never had any issues with viruses getting through. But my
groups are private groups with membership needing to be approved. Maybe
different for public groups.

Likewise with my email, I have disabled the server side filtering and
do it all myself with Mailwasher.

Dave

On 20 Aug 2018 at 20:24, Mark Fletcher wrote:

My default implementation would be to turn it on so that it blocks all
emails, files and photos that it finds has a virus or phishing attempt.
Do you see any reason to not do it this way?

http://davesergeant.com


Michael Capelle <mike.capelle@...>
 

I agree with this Mark.
 
 

Sent: Monday, August 20, 2018 10:24 PM
Subject: [beta] Virus scanning
 
Hi All,
 
I've been testing virus/phishing scanning the last few weeks and I'm pretty confident that it's catching what it should. In testing, it's scanning all emails, all uploaded files and photos. And right now, if the sender is not a subscriber, it drops any emails it finds has a virus or phishing attack.
 
My default implementation would be to turn it on so that it blocks all emails, files and photos that it finds has a virus or phishing attempt. Do you see any reason to not do it this way?
 
The scanner I'm using is here: http://www.clamav.net/
 
 
Thanks,
Mark


Ken Schweizer
 

Hi Mark,

 

My questions are:

Will the Owners/Moderators know that a message was blocked?

Will we know how many are blocked each day?

When will it start?

 

Yahoo blocked messages and never notified us what, why and how many. It became a disaster not knowing.

 

Ken

 

"And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book." God

 

From: main@beta.groups.io [mailto:main@beta.groups.io] On Behalf Of Mark Fletcher
Sent: Monday, August 20, 2018 10:25 PM
To: beta@groups.io
Subject: [beta] Virus scanning

 

Hi All,

 

I've been testing virus/phishing scanning the last few weeks and I'm pretty confident that it's catching what it should. In testing, it's scanning all emails, all uploaded files and photos. And right now, if the sender is not a subscriber, it drops any emails it finds has a virus or phishing attack. 

 

My default implementation would be to turn it on so that it blocks all emails, files and photos that it finds has a virus or phishing attempt. Do you see any reason to not do it this way?

 

The scanner I'm using is here: http://www.clamav.net/

 

 

Thanks,

Mark


 

Chris,

the only question I have is will group owners know what emails are rejected?

Hopefully these will be activity logged like any other rejection.

Shal


Dave Wade
 

Mark,

 

Yes scanners can catch spam/phish/malware, the trouble is that virus scanners are tuned for high detection rate because any one choosing a virus scanner will invariably choose the one with the highest detection rate.

Of course this usually equates to a high false positive rate, but no one ever tests for this, and figures for false positives are notoriously hard to find.

This can be a real pain as it often results in critical messages, for example those about SPAM, things containing copies of bad headers in the message body, things where you are trying to send samples of VBScript.

Have you tested what happens when you send innocent, but slightly malicious messages?

 

Dave

 

From: main@beta.groups.io <main@beta.groups.io> On Behalf Of Ken Schweizer
Sent: 21 August 2018 16:55
To: main@beta.groups.io; beta@groups.io
Subject: Re: [beta] Virus scanning

 

Hi Mark,

 

My questions are:

Will the Owners/Moderators know that a message was blocked?

Will we know how many are blocked each day?

When will it start?

 

Yahoo blocked messages and never notified us what, why and how many. It became a disaster not knowing.

 

Ken

 

"And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book." God

 

From: main@beta.groups.io [mailto:main@beta.groups.io] On Behalf Of Mark Fletcher
Sent: Monday, August 20, 2018 10:25 PM
To: beta@groups.io
Subject: [beta] Virus scanning

 

Hi All,

 

I've been testing virus/phishing scanning the last few weeks and I'm pretty confident that it's catching what it should. In testing, it's scanning all emails, all uploaded files and photos. And right now, if the sender is not a subscriber, it drops any emails it finds has a virus or phishing attack. 

 

My default implementation would be to turn it on so that it blocks all emails, files and photos that it finds has a virus or phishing attempt. Do you see any reason to not do it this way?

 

The scanner I'm using is here: http://www.clamav.net/

 

 

Thanks,

Mark


Jim Higgins
 

I don't expect scanning to change anything here for me since my groups use plain text and no attachments in the first place.

Actions? Perhaps DROP ALL and DROP ATTACHMENT ONLY should be available... as well as maybe some sort of "Quarantine for Review/Moderation by Group Owner" option.

Notification? Notify Owner, Notify Sender, Notify Both seem like decent options. Notify Owner (or both) seems to go hand in hand with an action of "Quarantine for Review..." (above).

Jim H



Received from Mark Fletcher at 8/21/2018 03:24 AM UTC:

Hi All,

I've been testing virus/phishing scanning the last few weeks and I'm pretty confident that it's catching what it should. In testing, it's scanning all emails, all uploaded files and photos. And right now, if the sender is not a subscriber, it drops any emails it finds has a virus or phishing attack.

My default implementation would be to turn it on so that it blocks all emails, files and photos that it finds has a virus or phishing attempt. Do you see any reason to not do it this way?

The scanner I'm using is here: <http://www.clamav.net/>http://www.clamav.net/

Thanks, Mark


 

Mark,

> My default implementation would be to turn it on so that it blocks all
> emails, files and photos that it finds has a virus or phishing
> attempt.
> Do you see any reason to not do it this way?

"Block" = "Drop" or "Reject"?

Drop is a very severe action, and I'm not entirely sure it should be done even with non-subscribers. With subscribers at the least I'd recommend "reject" (and add to the Activity log).

As Jim and some others, I was thinking maybe have a group option to put those from subscribers in the pending queue, prominently marked as containing potentially harmful content. This would serve the small fraction of groups who might be studying such things, or might be sharing harmless executable files that trigger a false positive.

I'm sympathetic because once long ago forwarding a message to abuse@... or spam@... was a common way certain senders requested that non-users (of their service) should report "bad" messages coming from their service. But I had an ISP that blocked suspicious messages outbound by me, so I couldn't send the requested report.

I don't think I would go as far as Lena suggests, and moderate them without that being a group option; I'm concerned that few group moderators would have the knowledge to make a safe decision for their group. A choice between "moderate" or "reject" might be useful, with "reject" the default.

By the way, I assume none of the above applies to the boatloads of absolute junk from invalid sources (malware-infected PCs and the like) that I presume you've been dropping all along. Those deserve the black hole treatment.

Shal


Marv Waschke
 

On Tue, Aug 21, 2018 at 09:42 PM, Shal Farley wrote:
I don't think I would go as far as Lena suggests, and moderate them without that being a group option; I'm concerned that few group moderators would have the knowledge to make a safe decision for their group. A choice between "moderate" or "reject" might be useful, with "reject" the default.
Agree with Shal on this. An email reflector like groups.io, is a multiplier-- it turns a single email into many emails. Cybercriminals love this. Send out a malevolent email to a single address and, depending on the size of the group, the poison goes to hundreds or thousands of potential victims. And those victims are predisposed to swallow the poison because it comes from a familiar source that they intentionally subscribed to. Even better if the email spoofs the name of a prominent member. This is a hacker's dream setup. These criminals are not nice people. Give them a chance and they will hurt you.

Rejecting is annoying, but aggressively scrubbing malware from multipliers like groups.io is good policy in my book. Moderators should hesitate and  consider carefully a decision to take the "moderate" option. Letting a malevolent email loose on your group could destroy it. Look at the annoyance of automatic rejection as a price a small price paid for the convenience and pleasure you get from membership in a groups.io group.

Best, Marv


 

On Tue, Aug 21, 2018 at 9:42 PM, Shal Farley <shals2nd@...> wrote:

I don't think I would go as far as Lena suggests, and moderate them without that being a group option; I'm concerned that few group moderators would have the knowledge to make a safe decision for their group. A choice between "moderate" or "reject" might be useful, with "reject" the default.


Ok, so new group option for dealing with spam: either moderate or reject, with reject being the default. Rejected messages will be logged in the activity log. If I reject a message, should it bounce back to the sender, or should I blackhole it?

If a message in the archives is flagged as having a virus or phishing attack, should I put a banner on the page saying so? (and should I go back through the archives doing scans)?

 
By the way, I assume none of the above applies to the boatloads of absolute junk from invalid sources (malware-infected PCs and the like) that I presume you've been dropping all along. Those deserve the black hole treatment.

The fact that many/most groups don't accept messages from non-subscribers acts as a natural prevention for a lot of this crap. I don't accept smtp connections from IP addresses that don't have reverse DNS records. I use a few blocklists as well, for all connections to the site, not just email. I haven't done anything with SPF and DKIM data yet.

Thanks,
Mark

 


Dave Sergeant
 

I take it this has not been implemented yet Mark, I see no options for
dealing with spam other than the existing ones under 'spam control' for
which in our case 'restricted membership' is the only relevant one.

Will there be an option to disable spam checking? I strongly feel there
should due to false positives, especially in private groups which
rarely have spam issues. I only look in the activity log rarely and
only if I have issues, 'moderation' of posts is an unwelcome extra
burden which I would really not want to do. Our groups just don't
suffer from spam, I would not really want false positives to get in the
way of an otherwise excellently running service.

Dave

On 22 Aug 2018 at 22:09, Mark Fletcher wrote:

Ok, so new group option for dealing with spam: either moderate or
reject, with reject being the default. Rejected messages will be logged
in the activity log. If I reject a message, should it bounce back to the
sender, or should I blackhole it?

http://davesergeant.com


 

Mark,

If I reject a message, should it bounce back to the sender, or should
I blackhole it?
Given that the sender passed a reverse-DNS I'd say it is safe to bounce it back. Chances are the message was sent by a compromised account at an otherwise legit service. (And maybe the rejection lets them know they've got a problem user?).

If a message in the archives is flagged as having a virus or phishing
attack, should I put a banner on the page saying so?
On the whole I'd say "yes".

The counter-argument is that if the group's mods accepted the message then they might not appreciate having the (presumed false-positive) marking on the message. But I think that the members deserve to know that there was at least some doubt about this content.

(and should I go back through the archives doing scans)?
Optional, but probably a good idea. The question is what you'd do besides mark them. I think adding entries for them to the Activity log may be sufficient (for mods to go find them if they want).

I haven't done anything with SPF and DKIM data yet.
One step at a time. Though I might have expected these before content scanning. But I may have a skewed view of their relative difficulty and effectiveness (eg: these don't apply to uploads).

Shal


 

Dave,

Will there be an option to disable spam checking?
Keep in mind this isn't about simple spam. This is about content which may be malware-infected or a phishing attempt. Detecting these specific things is likely to be much less prone to false positives than a generic spam filter.

Shal


 

Hi Mark,

If I reject a message, should it bounce back to the sender,
or should I blackhole it?
Reject (5xx) during inbound SMTP-session.

If a message in the archives is flagged as having a virus or phishing
attack, should I put a banner on the page saying so? (and should I go back
through the archives doing scans)?
At least give moderators the option to silence false positives which are inevitable, especially about phishing.

--
Lena


Sharon Villines
 

Rejecting is annoying, but aggressively scrubbing malware from multipliers like groups.io is good policy in my book. Moderators should hesitate and consider carefully a decision to take the "moderate" option. Letting a malevolent email loose on your group could destroy it. Look at the annoyance of automatic rejection as a price a small price paid for the convenience and pleasure you get from membership in a groups.io group.
How likely is it that a clean message will be identified as infected? We aren’t talking about spam which is identified on the basis of words used, etc. Right?

If the messages are being scanned for malware, is it safe to allow attachments? I have a large public list on which we have rejected attachments for years. Since my personal malware software finds viruses in my non-list email regularly, it certainly is still getting through whatever other email systems see it.

Sharon
----
Sharon Villines
TakomaDC@Groups.io
"Neighbors Talking to Neighbors”
Takoma Park DC and MD


 

I would lean toward dropping rather than bouncing spam/malware/phishing, just because the system on the other end might misclassify groups.io as the source of the malware.

If you do bounce it for malware, whatever triggered the malware alert (attachment or link to dangerous site) should be stripped from the bounce message to avoid this.

JohnF


Gerald Boutin <groupsio@...>
 

On Thu, Aug 23, 2018 at 11:19 AM, JohnF wrote:
I would lean toward dropping rather than bouncing spam/malware/phishing, just because the system on the other end might misclassify groups.io as the source of the malware.

If you do bounce it for malware, whatever triggered the malware alert (attachment or link to dangerous site) should be stripped from the bounce message to avoid this.

JohnF

I am 100% in favor of reject and not bouncing.

If you want more info - read on here: http://www.dontbouncespam.org/

--
Gerald