[wp-trac] [WordPress Trac] #50510: Improve security of wp_nonce implementation

[WordPress Trac]

#50510: Improve security of wp_nonce implementation
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 Reporter:  chaoix             |       Owner:  (none)
     Type:  enhancement        |      Status:  new
 Priority:  normal             |   Milestone:  Awaiting Review
Component:  Security           |     Version:
 Severity:  normal             |  Resolution:
 Keywords:  reporter-feedback  |     Focuses:
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Comment (by chaoix):

 I have provided an updated implementation of my changes to the nonce
 algoritm with more detailed comment.

 The benefits of these changes are:
 * Uses the sha512/sha256 hashing algorithm for increased nonce length and
 performance improvements with longer nonce actions. Longer actions prevent
 brute forcing of the nonce for known action names. MD5 was the previous
 hashing algorithm used and is not secure enough for what nonces are being
 used for in WordPress. https://en.wikipedia.org/wiki/MD5#Security
 * Adds complexity to the nonce has algorithm to make them more difficult
 to reverse engineer using rainbow tables.
 * Adds a browser id to the nonce action to help prevent known hash reuse.
 * Reject nonces from browsers with no or invalid user agent strings. This
 will prevent lazy bots from submitting requests.

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Ticket URL: <https://core.trac.wordpress.org/ticket/50510#comment:4>
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