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The Forgot Username form might provide information about user accounts

High
surli published GHSA-vh5c-jqfg-mhrh Feb 4, 2022

Package

maven org.xwiki.platform:xwiki-platform-administration-ui (Maven)

Affected versions

< 12.10.5, 13.0 and 13.1

Patched versions

12.10.5, 13.2RC1

Description

Impact

It's possible to know if a user has or not an account in a wiki related to an email address, and which username(s) is actually tight to that email by forging a request to the Forgot username page. Note that since this page does not have a CSRF check it's quite easy to perform a lot of those requests.

Patches

This issue has been patched in XWiki 12.10.5 and 13.2RC1. Two different patches are provided:

  • a first one to fix the CSRF problem
  • a more complex one that now relies on sending an email for the Forgot username process.

Workarounds

It's possible to fix the problem without uprading by editing the ForgotUsername page in version below 13.x, to use the following code:

<content>{{velocity}}
#set($email = "$!request.get('e')")
#if($email == '' || !$services.csrf.isTokenValid($request.form_token))
{{translation key="xe.admin.forgotUsername.instructions"/}}
{{html}}
&lt;form method="post" action="$doc.getURL()" class="xformInline"&gt;
&lt;div&gt;
&lt;label for="e"&gt;$services.localization.render('xe.admin.forgotUsername.email.label')&lt;/label&gt;
&lt;input type="text" id="e" name="e"/&gt;
&lt;input type="hidden" name="form_token" value="$services.csrf.getToken()"/&gt;
&lt;span class="buttonwrapper"&gt;
&lt;input type="submit" value="$services.localization.render('xe.admin.forgotUsername.submit')" class="button"/&gt;
&lt;/span&gt;
&lt;/div&gt;
&lt;/form&gt;
{{/html}}
#else
#set($query = $services.query.hql(", BaseObject obj, StringProperty prop where obj.name = doc.fullName and obj.className = 'XWiki.XWikiUsers' and prop.id.id = obj.id and prop.id.name = 'email' and LOWER(prop.value) = :email").bindValue('email', $email.toLowerCase()))
#set($results = $query.execute())
## If local user does not exist check global user
#if($results.size() == 0 &amp;&amp; ${xcontext.database} != ${xcontext.mainWikiName})
#set($results = $query.setWiki("${xcontext.mainWikiName}").execute())
#end
#set ($emailError = false)
#if($results.size() != 0)
## Send the email
#set ($from = $services.mail.sender.configuration.fromAddress)
#if ("$!from" == '')
#set ($from = "no-reply@${request.serverName}")
#end
## The mail template use $usernames to display the results.
#set ($usernames = $results)
#set ($mailTemplateReference = $services.model.createDocumentReference('', 'XWiki', 'ForgotUsernameMailContent'))
#set ($mailParameters = {'from' : $from, 'to' : $email, 'language' : $xcontext.locale})
#set ($message = $services.mail.sender.createMessage('template', $mailTemplateReference, $mailParameters))
#set ($discard = $message.setType('Forgot Username'))
#macro (displayError $text)
{{html}}
&lt;div class="xwikirenderingerror" title="Click to get more details about the error" style="cursor: pointer;"&gt;
$services.localization.render('xe.admin.forgotUsername.error.emailFailed')
&lt;/div&gt;
&lt;div class="xwikirenderingerrordescription hidden"&gt;
&lt;pre&gt;${text}&lt;/pre&gt;
&lt;/div&gt;
{{/html}}
#set ($emailError = true)
#end
## Check for an error constructing the message!
#if ($services.mail.sender.lastError)
#displayError($exceptiontool.getStackTrace($services.mail.sender.lastError))
#else
## Send the message and wait for it to be sent or for any error to be raised.
#set ($mailResult = $services.mail.sender.send([$message], 'database'))
## Check for errors during the send
#if ($services.mail.sender.lastError)
#displayError($exceptiontool.getStackTrace($services.mail.sender.lastError))
#else
#set ($failedMailStatuses = $mailResult.statusResult.getAllErrors())
#if ($failedMailStatuses.hasNext())
#set ($mailStatus = $failedMailStatuses.next())
#displayError($mailStatus.errorDescription)
#end
#end
#end
#end
## We always display a success message even if there's no user found to avoid disclosing information
## about the users registered on the wiki.
#if (!$emailError)
{{success}}
$services.localization.render('xe.admin.forgotUsername.emailSent', ["$email"])
{{html}}
&lt;div&gt;
&lt;a href="$xwiki.getURL('XWiki.XWikiLogin', 'login')"&gt;$services.localization.render('xe.admin.forgotUsername.login')&lt;/a&gt;
&lt;/div&gt;
{{/html}}
{{/success}}
#end
#end
{{/velocity}}</content>

In version after 13.x it's also possible to edit manually the forgotusername.vm file, but it's really encouraged to upgrade the version here.

References

For more information

If you have any questions or comments about this advisory:

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVE ID

CVE-2021-32732