I reversed Tower of Fantasy's anti-cheat driver: a BYOVD toolkit never loaded

Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by charcircuit on Friday February 06, 2026 @01:54AM (#46909918)

Exactly, which is why Microsoft should be writing the one writing the kernel code needed for ensuring integrity of games. Microsoft needs to develop ways to allow games to run in an isolated VM that is hardware protected from the main operating system and ensures strong hardware security so cheaters can not simply attach malicious devices to the PCI bus to DMA sensitive data.

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by 15155 on Friday February 06, 2026 @04:28AM (#46910776)

> attach malicious devices to the PCI bus to DMA sensitive data

How do you do this in modern system with TPMs and IOMMU enabled?

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by charcircuit on Friday February 06, 2026 @04:49AM (#46910907)

Sadly not all Windows machines are able to use kernel DMA protection, so for those machines nothing will stop you.

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by 15155 on Friday February 06, 2026 @09:19AM (#46913129)

The obvious next step is to disallow those elderly machines once a critical mass of users have modern-enough equipment. We're almost there.

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by direwolf20 on Friday February 06, 2026 @05:51AM (#46911324)

You pretend to be a device with a driver not compatible with IOMMU

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by 15155 on Friday February 06, 2026 @09:22AM (#46913176)

This is a good move, but why isn't the anti-cheat software just refusing to operate on systems with these devices attached?

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by direwolf20 on Saturday February 07, 2026 @04:51AM (#46922613)

Because banning players from playing your game leads to refunds and bad publicity

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by uhuhuhuhuhuh on Friday February 06, 2026 @04:23PM (#46918340)

Flash custom firmware emulating some benign "donor card".

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by direwolf20 on Friday February 06, 2026 @05:50AM (#46911321)

As an indie game developer, how do I get my game into this system and how do I debug it?

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by charcircuit on Friday February 06, 2026 @05:59AM (#46911381)

For this theoretical feature Windows would do it automatically for apps that would opt in.

For debugging you would either not have this feature or enabled, or you would build a custom build that included a debugger in the secure environment. If you needed to connect to production servers you could whitelist your account to be ignored by the anticheat since your server would know you are not playing with an official build.

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by direwolf20 on Friday February 06, 2026 @08:33AM (#46912619)

If it's a simple flag in the executable file header, what stops a cheat program setting the same flag and getting into the sandbox?

Or a cheat program combining itself with the game executable, and setting the flag so other processes can't interrogate whether it contains a cheat.

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by Orphis on Friday February 06, 2026 @09:49AM (#46913496)

You don't "get into the sandbox", if a cheat program opted in, they would be launched into a separate instance that's distinct from the game.

And you would sign your files, which get verified by the integrity platform and allow you to authenticate with the servers securely.

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by direwolf20 on Friday February 06, 2026 @04:55PM (#46918662)

Sounds very similar to total platform lockdown

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Re:I reversed Tower of Fantasy's anti-cheat driver: a BYOVD ... by charcircuit on Friday February 06, 2026 @08:25PM (#46920363)

It is similar except it's only a total lockdown of the sandbox.

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