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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Interesting input that we should not take lightly and ought to put serious thought on it. A few things to consider:<o:p></o:p></span></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoNormal" style="color:black;mso-list:l0 level1 lfo1">Let’s be cautious to not over-produce variants due to corner cases. The example below is a second-level domain name and our work is relevant for the top-level. Unlike second-level, the top level
has an extraordinarily high bar for existence (i.e. there needs to be application round in process, there are substantial application fees, technical and financial requirements to run a registry, etc.). Therefore, I find it very unlikely that an entity would
even apply for approval for a top-level label that is visually confusable of another. Even in that event, ICANN has other mechanisms (e.g. String Similarity Review, DNS Stability Review) to stop similar applied-for TLDs from progressing in the application
process. <o:p></o:p></li><li class="MsoNormal" style="color:black;mso-list:l0 level1 lfo1">Security risk analysis deserves a place in our work, but should first focus on real issues and not hypothetical ones. Do we have examples of this being observed in practice? <o:p></o:p></li><li class="MsoNormal" style="color:black;mso-list:l0 level1 lfo1">This input deviates from past guidance, so we need to assess the ramifications to our principles of inclusion for in-script and cross-script variants. On this note, I appreciate that any additional
work will delay our submission to IP before our workshop in early October. But I think it is better that we take the time to deliver a quality work.<o:p></o:p></li></ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-Dennis<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">Latingp <latingp-bounces@icann.org> on behalf of Sarmad Hussain <sarmad.hussain@icann.org><br>
<b>Date: </b>Wednesday, August 29, 2018 at 2:58 AM<br>
<b>To: </b>Latin GP <latingp@icann.org><br>
<b>Subject: </b>[EXTERNAL] [Latingp] From IP: Diacritics below a security risk?<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">Dear Latin GP members <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">Kindly find below some feedback from IP for your consideration.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">Regards <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">Sarmad <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in"><br>
<br>
<o:p></o:p></p>
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<br>
TO: LatinGP<br>
FROM: IP<br>
<br>
There are recent and widely published examples of phishing attacks using Latin IDNs in which the key features involved were diacritics below the letter. Here is an example:<o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif"><img width="438" height="286" style="width:4.5625in;height:2.9791in" id="_x0000_i1028" src="cid:image001.png@01D4404A.93EF5440" alt="cid:part1.E6E9F88C.32B00687@ix.netcom.com"></span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">Of all diacritics, diacritics below can be difficult to distinguish or be prone to clipping -- there is less space below the baseline than between the typical lowercase glyph and the top
of the line.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">The example given above shows a further interaction with URL underlining - and not all display engines actually do as nice a job interrupting the underline as in the screen shot above.
For example, here is how one system will render this (using a designated UI font - Segoe UI):</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif"><img width="185" height="32" style="width:1.927in;height:.3333in" id="_x0000_i1027" src="cid:image002.png@01D4404A.93EF5440" alt="cid:part2.59964F92.16B1BC0B@ix.netcom.com"></span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">Note, this code point (U+1E33) is in the MSR as is (U+1E35 LATIN SMALL K WITH LINE BELOW).</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif"><img width="197" height="47" style="width:2.052in;height:.4895in" id="_x0000_i1026" src="cid:image003.png@01D4404A.93EF5440" alt="cid:part3.99B9649E.C3C335FC@ix.netcom.com"></span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">The second example contains U+1E35 -- while the effect does not show equally at all type sizes, from 12pt and below the LINE BELOW is reliably hidden. Here are the two examples at 10pt</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif"><img width="101" height="56" style="width:1.052in;height:.5833in" id="_x0000_i1025" src="cid:image004.png@01D4404A.93EF5440" alt="cid:part4.B43CE3FD.8C84EACF@ix.netcom.com"></span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">The issue is not limited to "K". We see "B", "D", "L" and "N" with both DOT and LINE BELOW and "M" and "H" with DOT BELOW, all on the same page in the MSR.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">It can be argued users have no working understanding of typography and would not reliably interpret small gaps or bulges in the underline as being related to an unfamiliar code point.
This appears to make all diacritics below security-sensitive, however, the initial determination belongs to the relevant GPs.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">Note by the way that the Devanagari LGR treats sequences containing NUKTA (a dot below) as variants in at least some cases and recent community comments for that script are calling for
more variant sequences. However, while the feature is graphically analog (dot below), each script works differently and there is no single a-priori solution.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">The IP would like to encourage the LatinGP (and any other GP facing cases like this) to explicitly examine this example and other cases like it, where code points can become indistinguishable
in common usage scenarios for IDNs, and formally conclude whether and how to take these into account when designing their LGR.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">At this point, the IP would expect the GP to:</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">* explicitly discuss this and other scenarios like it</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">* evaluate whether they constitute a security risk to the Root Zone</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">* come up with a reasoned decision as to whether and how to address them in the design of the Latin GP; and finally</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">* document both the decision and its rationale.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">In coming to a decision, the GP may resolve:</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">1) to make them variants</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">2) to list them for attention as confusable</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">3) to take no action, because the GP feels that they do not represent a special security risk.</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-family:"Arial",sans-serif">As part of the review of the Latin LGR, the IP will look at the background and rationale offered by the Latin GP in coming to its conclusion; note that if the IP feels that the facts considered
and rationale documented do not support the conclusion reached by the GP it may raise objections at that time.</span><o:p></o:p></p>
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