Educause Security Discussion mailing list archives

Re: Measures of detecting breached email accounts


From: Frank Barton <bartonf () HUSSON EDU>
Date: Tue, 5 Dec 2017 15:39:08 -0500

Keenan, that depends on what services you are using. I'm not familiar with
Office365, but depending on the login types that they allow, (ADFS, SAML)
you would control the login page, and could filter ahead of people getting
to the login page.

Frank

On Tue, Dec 5, 2017 at 3:33 PM, Keenan Martinez <
0000004218ecec53-dmarc-request () listserv educause edu> wrote:

Frank,



Thank you for your feedback, I garner the procedure can be automated but
is not 100% successful.



I question if there is more we can do besides enabling MFA, DKIM, DMARC
and other procedure Universities utilise in reducing account breaches and
spamming.



At our University, our policies govern that all employees must utilise
MFA. However, due to limited resources I am reluctant to expand the
policy to our student accounts. It leads the team to perform the process
mentioned in my first email, of sorting logs via country.



I believe there should be (if a system already exists), which allows you
to allow logins only via region. I.e. email account will only accept
logins from your region (mine being the Caribbean) and deny login from
other areas, with an option to request access. My view may be far fetched,
but I think it would assist greatly with account breaches.



Regards,







*From: *The EDUCAUSE Security Constituent Group Listserv <
SECURITY () LISTSERV EDUCAUSE EDU> on behalf of Frank Barton <
bartonf () HUSSON EDU>
*Reply-To: *The EDUCAUSE Security Constituent Group Listserv <
SECURITY () LISTSERV EDUCAUSE EDU>
*Date: *Tuesday, 5 December 2017 at 9:50 am
*To: *"SECURITY () LISTSERV EDUCAUSE EDU" <SECURITY () LISTSERV EDUCAUSE EDU>
*Subject: *Re: [SECURITY] Measures of detecting breached email accounts



We put a spam-filter on our outbound email queue, and have found that that
is a pretty good indicator of detecting compromised accounts. The filter
also emails us (me) on blocked outbound spam, and when I start hearing my
phone go ding-ding-ding-ding-ding-ding-ding, it's never a good time.



We've also found that compromises tend to come in waves, and be
"trackable". Once we identify a compromised account, we then look at
logins, and start looking for patterns in other accounts. Matching IP
addresses in a short window is a good indication. We also then found that
there was typically a 2-step compromise pattern. The initial compromise
would show up as a single login from an IP address that was not in the
normal use pattern. a couple days later we would see the login that would
then try to flood spam out to the interwebs.



We've tried to automate this as much as possible, but a lot of it falls
under the german word "Gefuhlsache" it's a matter of feeling.



That being said, I did write a script that would pull down the last couple
weeks of Google logins logs, and look for out-of-the country IPs, this had
some success among our staff and faculty members during the academic year,
but a lot less over breaks, and when looking at students.



Stepping away from account compromise, we run a, *very* locked down, SFTP
server on the amazon cloud, one of the things I have installed is fail2ban.
I've build up a manual list of netblocks that we just block outright from
accessing the server. I am somewhat hesitant to expand that to other
services, but the thought has crossed my mind.



Frank



On Mon, Dec 4, 2017 at 9:56 PM, Valdis Kletnieks <valdis.kletnieks () vt edu>
wrote:

On Mon, 04 Dec 2017 23:19:28 +0000, Keenan Martinez said:

I am inquiring about techniques members undertake to proactively detect
breached email accounts and how the process of converting IP addresses to
countries be simplified?

Doing exception analysis on successful *and failed* logins is a good start
-
and done a *lot* more frequently than "monthly".  You'll very quickly
learn to
tell the difference between dictionary attacks trying to get into *any*
userid, and
targeted attacks on a specific user - if one of your VPs is hit overnight
with 17 failed
login attempts from Ukraine while they're sleeping in the Carribean night,
you have
a potential problem.

Another thing to monitor is for unusual traffic patterns, both inbound and
outbound.
For instance, my userid gets a *lot* of inbound mail from software-related
lists, and lots of
usually small outbound mail to pretty much all over the planet.  But if I
suddenly send out
a series of 28 outbound emails that are 17M in size each, it might
indicate that my userid
has been compromised and is being used to exfiltrate sensitive data.

Also, look at traffic levels for things other than email - http/https,
ftp, and so on.  Suddenly
high traffic levels from a user/machine that hasn't been historically very
active is a possible
sign of a problem - especially large volumes of outbound data indicating
possible uploads
of sensitive info.

There's not a lot of "proactive detection" that you can really do - in most
cases, you're either reacting to logs/audit trails, or doing proactive
stuff up
front to *prevent* the breach in the first place.

Stuff like the SANS "Securing the Human" is helpful to get your users up
to speed.
Checking for easily broken passwords, enforcing stronger passwords and/or
multi-factor
authentication for users with critical access, making sure that your users
have their
machines patched and appropriate security/AV software installed and up to
date..

etc etc etc.  All the usual "how to keep your users from being
hacked/phished" stuff....





--

Frank Barton

Security+, ACMT

IT Systems Administrator

Husson University
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-- 
Frank Barton
Security+, ACMT
IT Systems Administrator
Husson University

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