<p>WannaCry worm that plagued many computers around the world apparently can be decrypted without the $600 ransom payment. Adrien Guinet, a French researcher claims that he has found a solution for WannaCry file encryption for Windows XP systems. He was able to discover the prime numbers that make up the WannaCry private key. A private key is sold to infected victims in order to decrypt the files.</p>
<p><a href="https://www.wincert.net/wp-content/uploads/2017/02/security.jpg"><img class="alignnone wp-image-2012 size-full" src="https://www.wincert.net/wp-content/uploads/2017/02/security.jpg" alt="prime numbers" width="640" height="426" /></a></p>
<blockquote>
<p dir="ltr" lang="en">I got to finish the full decryption process, but I confirm that, in this case, the private key can recovered on an XP system <a href="https://twitter.com/hashtag/wannacry?src=hash">#wannacry</a>!! <a href="https://t.co/QiB3Q1NYpS">pic.twitter.com/QiB3Q1NYpS</a></p>
<p>— Adrien Guinet (@adriengnt) <a href="https://twitter.com/adriengnt/status/865168794586632192">May 18, 2017</a></p></blockquote>
<p>In order for this solution to work your <span style="text-decoration: underline;">PC must not have been rebooted</span> after the infection. WannaCry does not erase the prime numbers from memory before it frees associated memory. So, if that&#8217;s the case and associated memory haven&#8217;t been reallocated, a prime numbers could still be in memory.</p>
<p>Guinet managed to decrypt his files using these prime numbers that were still located in memory. His software called &#8220;Wannakey&#8221; has been released to the public and you can use it for free. Have in mind that Wannakey software has not been tested on a very large number of computers so it&#8217;s hard to say that it will work for everyone.</p>
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