<div dir="ltr"><div>The problem that I'm concerned about is that a lot of organizations that add SMS 2FA often end up resorting to it as a crutch. So let's say that person A did set up TOTP. But then person B finds enough information about person A to do a social engineering attack. Person B still doesn't have access to person A's TOTP application, but they know person A's phone number (this is generally easy to find, I wouldn't be surprised if many WHOIS phone numbers are associated with accounts on ARIN, or white/yellow pages). So they contact ARIN pretending to be person A, claiming to have lost their TOTP. So because SMS is now an option for authentication ARIN reverts the 2FA to SMS because it's easy. SIM hijack or interception is easy enough. Well, now person B's only hurdle is going to be the password anyway. They could have tried to brute force earlier and gotten the correct password. Or also attempt a password reset when resetting the 2FA.<br><br></div>So the biggest thing I would impart to ARIN is do not trust SMS at all. I understand it's a stop gap that has high appeal for its ease of deployment. But do not trust it when doing account recoveries, or 2FA resets, etc.<br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 24, 2022 at 7:25 PM Chris Woodfield <<a href="mailto:chris@semihuman.com">chris@semihuman.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;"><speaking_for_myself.disclaimer><br><div><br></div><div>If given the choice between and SMS-based second factor and no second factor at all, which would you choose? </div><div><br></div><div>I agree that SMS is the weakest form of 2FA of the options being considered, and I would not be happy with a system that only supported it and did not support TOTP or FIDO2. I would find it highly unlikely, however, that requiring 2FA for logins and *not* allowing SMS as an option will prove a successful approach, however - it’s Just Complex Enough that I can see a far-too-large segment of ARIN’s user base requiring quite a bit of support to enable it. </div><div><br></div><div>-C</div><div><br><blockquote type="cite"><div>On May 24, 2022, at 12:23 PM, Max Krivanek via ARIN-consult <<a href="mailto:arin-consult@arin.net" target="_blank">arin-consult@arin.net</a>> wrote:</div><br><div><div dir="ltr"><div>Hi,</div><div><br></div><div>I find SMS highly insecure since it can be intercepted (it goes across the system in plain text, similar to HTTP) and there is also SIM hijacking. This article by Krebs goes into more detail of why it's insecure.<br><a href="https://krebsonsecurity.com/2021/03/can-we-stop-pretending-sms-is-secure-now/" target="_blank">https://krebsonsecurity.com/2021/03/can-we-stop-pretending-sms-is-secure-now/</a><br><br></div><div>The fact that major financial institutions use it is a detriment to them. As TOTP or FIDO2 are way more secure. But this is where reality hits the road. Most people will not want to set up TOTP or FIDO2, but as long as those of us who are more security minded can make sure SMS or the phone number in general cannot be used for authentication purposes I would be fine with including it as a stop gap.<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 24, 2022 at 1:59 PM Richard Laager <<a href="mailto:rlaager@wiktel.com" target="_blank">rlaager@wiktel.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I believe ARIN absolutely should require 2FA. Your actual experience with dictionary attacks confirms that.<br>
<br>
SMS 2FA seems like a pragmatic compromise. I’m aware that SMS is generally considered a less secure 2nd factor, but: 1) I’m not sure how much less secure it really is. It obviously cannot be worse than a password alone. 2) Major financial institutions seem okay with it. 3) It might be necessary in practice to get people to turn on / accept 2FA.<br>
<br>
You will have to think hard about recovery procedures. They will become the weak link in the security.<br>
<br>
-- <br>
Richard<br>
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</blockquote></div><br clear="all"><br>-- <br><div dir="ltr"><div dir="ltr"><span style="color:rgb(153,153,153)">Max Krivanek</span><br style="color:rgb(153,153,153)"><font color="#888888"><span style="color:rgb(153,153,153)">Managing Member</span><br><a style="font-family:arial,helvetica,sans-serif" href="http://www.codingdirect.com/" target="_blank"><span style="color:rgb(0,153,0)">Coding</span><b style="color:rgb(153,153,153)">Direct</b></a><br>
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</blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><span style="color:rgb(153,153,153)">Max Krivanek</span><br style="color:rgb(153,153,153)"><font color="#888888"><span style="color:rgb(153,153,153)">Managing Member</span><br><a style="font-family:arial,helvetica,sans-serif" href="http://www.codingdirect.com/" target="_blank"><span style="color:rgb(0,153,0)">Coding</span><b style="color:rgb(153,153,153)">Direct</b></a><br>
<br>Phone: (682) 232-4867<a value="+18176015553"></a></font><br></div></div>