Last modified: 2012-11-28 13:55:09 UTC

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Bug 2593 - Non-printing characters allowed in registration
Non-printing characters allowed in registration
Product: MediaWiki
Classification: Unclassified
User login and signup (Other open bugs)
All All
: Low enhancement with 1 vote (vote)
: ---
Assigned To: Nobody - You can work on this!
: testme
Depends on: 1524
Blocks: 3985
  Show dependency treegraph
Reported: 2005-06-28 22:28 UTC by Stefan Hidden
Modified: 2012-11-28 13:55 UTC (History)
2 users (show)

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Description Stefan Hidden 2005-06-28 22:28:32 UTC
The latest software upgrade at Wikipedia and other Wikimedia projects
reintroduces an old problem which allows registration of accounts containing
non-printing characters such as ­. This can allow vandals to "pretend"
to be someone else. For example, a vandal can regiser a username like
Grunt%C2%AD (not actually using %C2%AD but by placing the non-printing character
in the field...). I registered an account like this by creating a blank HTML
with only the content &­ and then Ctrl+A, Ctrl+C'ing it.
Comment 1 peter green 2005-06-29 22:03:41 UTC
imho the allowed stuff in usernames should be based on a whitelist. Using a
blacklist means that you will always risk missing stuff that vandals would find
Comment 2 Neil Harris 2005-07-01 16:53:42 UTC
See also Bug 2290: user impersonation using homographs for a wider perspective...
Comment 3 lɛʁi לערי ריינהארט 2005-10-14 14:51:46 UTC
see also

bug 1524: usernames should use unicode whitelist
Comment 4 Anu 2012-11-28 11:56:59 UTC
I tried to login within a "#$$%%%%" which throws the login error, "You have not specified a valid user name.". I also tried to do Ctrl^C, Ctrl^V, and other fields that I could think of. The form does allow you to enter illegal characters. So this issue is resolved for now.
Comment 5 Anu 2012-11-28 12:13:33 UTC

I am sorry about the last sentence in the last post. I meant to say I tested and tried to reproduce the error but with no success.
Comment 6 Andre Klapper 2012-11-28 13:55:09 UTC
(In reply to comment #4)
> I tried to login within a "#$$%%%%"

These are visible, printable characters. Comment 0 mentions "non-printing characters". See

I tried on (version 1.21wmf5) to create an account as Maly­acko (save as HTML file, open it in browser, copy from the browser display, as described in comment 0).


Login error
The name "Maly­acko" is not allowed to prevent confusing or spoofed usernames: Contains unassigned character U+00AD. Please choose another name.

So I consider this FIXED as there is a check in place (though I don't know where a blacklist or whitelist is located though, and which exact characters are covered by it).

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