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Timing attack on the password reset

Platform: ownCloud Server

Versions: 4.0.9, 4.5.1,

Date: 8/24/2012

Risk level: Medium


The “Lost Password” implementation is vulnerable to a Remote Timing Attack. The token used to secure the password reset is fetched from the database and compared to the user-specified value using the equals operator. An attacker successfully rebuilding the token can then specify an arbitrary password in POST which will overwrite the old password.

Please note that actual exploitation would require an attacker to be on the same LAN as the ownCloud server.

Affected Software

  • ownCloud Server < 4.5.1 (CVE-2012-5607)
  • ownCloud Server < 4.0.9 (CVE-2012-5607)

Action Taken

It is recommended that all instances are upgraded to ownCloud Server 4.5.1 or 4.0.10.


The ownCloud team thanks the following people for their research and responsible disclosure of the above advisory:

  • Andreas Fischer – ownCloud Inc. (bantu@owncloud.com) – Vulnerability discovery and disclosure.

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