The major issue here is that Mega's method for deriving the various cryptographic keys used to authenticate and encrypt files fails to check for key integrity. Dotcom reportedly expects his former Megaupload colleagues to testify against him, which perhaps explains his recommendation against using Mega. Authorities in the US are still trying to extradite Kim Dotcom, who founded Megaupload in 2005 and oversaw operations until its 2012 shutdown by the FBI. In doing so, they avoid extradition to the US Mega's former marketing director Finn Batato was also charged but died of cancer earlier this month. The last attack is a Bleichenbacher-style attack against MEGA’s RSA encryption mechanism."Ĭoincidentally, Mega's other co-founders Mathias Ortmann and Bram van der Kolk, pleaded guilty on Tuesday in New Zealand to participating in a criminal group and to deceiving artists for profit, for their involvement with Megaupload, the copyright-flouting predecessor of Mega.
"The next two attacks breach the integrity of file ciphertexts and allow a malicious service provider to insert chosen files into users’ cloud storage.
"The first two attacks exploit the lack of integrity protection of ciphertexts containing keys (henceforth referred to as key ciphertexts), and allow full compromise of all user keys encrypted with the master key, leading to a complete break of data confidentiality in the MEGA system," the paper explains. Mega chief architect Mathias Ortmann meanwhile published a blog post announcing a client software update addressing three of the five flaws identified by the researchers, promising further mitigations, and thanked the ETH Zurich boffins for responsibly reporting their findings. The findings, detailed on a separate website, proved sufficiently severe that Kim Dotcom, no longer affiliated with the file storage company, advised potential users of the service to stay away.
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