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The report for the 2024 security audit of the Mullvad app is now available
The third party security audit of the Mullvad VPN app has concluded that the app has a high security level. Some non-critical issues were found, and have been fixed to the extent possible.
They can do this by sending UDP packets with a unique size with the source address and port set to the internet service they are interested in, the destination IP to the exit VPN relay of the user. If the user has a connection with that internet service endpoint, eventually one packet will match the NAT table entry on the VPN relay and be forwarded down the tunnel. The threat model defined in the report makes it clear that it's virtually impossible to be fully protected against a very powerful attacker that can observe and manipulate internet traffic on a global scale.
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