The Hacker News
reports that threat actors could exploit several critical security vulnerabilities
in the MEGA cloud storage service to compromise user data confidentiality and integrity.
MEGA or nation-state attackers could leverage an RSA Key Recovery Attack to seize API infrastructure control and enable RSA private key recovery, a study from ETH Zurich researchers revealed. The report showed that the recovered key could then be used to facilitate plaintext recovery attacks, framing attacks, integrity attacks, and Guess-and-Purge Bleichenbacher attacks.
"Each user has a public RSA key used by other users or MEGA to encrypt data for the owner, and a private key used by the user themselves to decrypt data shared with them. With this [GaP Bleichenbacher attack], MEGA can decrypt these RSA ciphertexts, albeit requiring an impractical number of login attempts," said researchers. However, MEGA Chief Architect Mathias Ortmann emphasized that there has been no indication that the attack techniques have been used to compromise any user accounts.
"The reported vulnerabilities would have required MEGA to become a bad actor against certain of its users, or otherwise could only be exploited if another party compromised MEGA's API servers or TLS connections without being noticed," added Ortmann.