<p></p>
<h3 dir="auto">Problem</h3>
<p dir="auto">It is possible to spoof users by creating fake user accounts with names that look identical to the name of the real account but use different Unicode characters.</p>
<h3 dir="auto">Description</h3>
<p dir="auto">This happened yesterday with this account:<br>
real account: <a href="https://www.openstreetmap.org/user/limes11" rel="nofollow">https://www.openstreetmap.org/user/limes11</a><br>
fake account: <a href="https://www.openstreetmap.org/user/Iimes11" rel="nofollow">https://www.openstreetmap.org/user/Iimes11</a><br>
The real account starts with a lower case 'L' and the fake account starts with an upper case 'i'.</p>
<p dir="auto">The same thing is possible with e.g. the character 'a' which looks identical in Latin and Cyrillic alphabet. There is a good summary mentioning way more problematic characters on Wikipedia (1).</p>
<p dir="auto">A solution to this might be to check whether an account with a similar name already exists when creating a new account (looks like there already is a check that prohibits names that just differ in lower-/uppercase) or to prohibit the use of characters from more than one alphabets in new usernames.</p>
<p dir="auto">(1) <a href="https://en.wikipedia.org/wiki/IDN_homograph_attack" rel="nofollow">https://en.wikipedia.org/wiki/IDN_homograph_attack</a></p>
<h3 dir="auto">Screenshots</h3>
<p dir="auto"><em>No response</em></p>

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