Unlike most game mods (which are, to my knowledge, a distribution of a copy of modified game software), I'm writing a small desktop application which allows users to make their own custom changes (modifications/mods) to (their own copy) of the game by using the app.

The app will make a copy of some of the game's files (that they have) and then modify those copies. 0% of the app is, in of itself, copyrighted material (the game's code, etc.). I am writing this application from scratch. It is 100% my own creation.

In addition, it doesn't contain any logos, images, etc., from the game, and am I not planning on naming it anything which would make others feel that the application (or I) am associated with the game's publisher (or developers).

Edit 1: I figured out how to modify this game by manually sorting through (and figuring out) gibberish with a hex editor. (I did not decompile the game's files to see the original source code.) My application primarily makes hex edits.


Assuming that all of how I described the application above is true, if I distribute it on the internet free of charge, would there be any possibility of any potential copyright infringement, lawsuits, complaints, etc., from the game's publisher or developers to your knowledge?

Can they possibly "get me" for distributing my own software for free, even if my software literally doesn't contain any of their property (despite having the capability to modify their property)?

By my understanding of articles like this, https://hackerbot.net/faq/54-are-game-hacks-legal, I may be in the clear. But articles like this https://mttlr.org/2012/11/gaming-mods-and-copyright/ make me feel like maybe I shouldn't have started hacking games to begin with!

Important Note:

I am aware of issues with using game mods/hacks to get an unfair advantage in online competitive environments.

The primary purpose of my software is NOT to give an advantage in competitive online gaming, etc. It's merely to enjoy the game and play it causally. (Bring life back to a mostly abandoned game.)

It can technically be used to get an advantage with gameplay. Although I highly doubt this will ever be an issue (of the only two online competitive gaming platforms that I'm aware of, I am a moderator of one of them, and know the moderator of the other one), should it be that, in order me to avoid facing any consequences for distributing this software, it is necessary for me to make my app put a "watermark" of some kind in the modified copy of the game which it makes, let me know!

Edit 2: (Question 2) (This edit is a result of Neil Meyer's comment about the specific EULA of the game in question.)

The EULA of the (1999 PC) game in question, states (among other things):

You may not copy the Software (except as specifically permitted herein) and, except as expressly permitted by law, you may not modify, translate, reverse engineer, decompile, disassemble or create derivative works of the Software.

Clearly they do not permit copying the game (which I am not). I am therefore zeroing in on the clause:

except as expressly permitted by law

Does this mean that, if it's legal in the country where I live, then they (the publisher) do not object if I provide users (who also live in a country where it's legal to modify PC games) a means to modify this PC game?

  • I don't know the answer but the EFF's FAQ on reverse-engineering code might have some bearing on your situation, depending on how you figured out how to modify the existing code. Commented May 20, 2023 at 2:08
  • Thanks, I will look into that. (And I edited my question to also describe the manner in which I figured out how to modify the existing code, to be more clear.) Thanks again! Commented May 20, 2023 at 2:22
  • 3
    This all depends on the EULA of the game in question. Old games came with editors that actively encouraged modding, but then valve stole dota from blizzard and that concept died a sudden death.
    – Neil Meyer
    Commented May 20, 2023 at 4:16
  • Thanks, Neil. I looked at the EULA for the game in question, and I STILL have just one more question. (I appended it to the original post.) Commented May 20, 2023 at 14:25
  • 1
    Wad the 1999 game published by Nintendo? Do you want to take the risk they'll sue you anyway, even if they might be doomed to lose, simply to drain you of funds and shut down your service?
    – nick012000
    Commented May 21, 2023 at 8:08

2 Answers 2


The legal question is whether you would be vicariously liable for copyright infringement, by distributing this software. You can read here the requirements for vicarious liability, the principles having been established by cases such as MGM v. Grokster, A&M Records v. Napster, Perfect10 v. Giganews. First, someone else must be found guilty of copyright infringement. Then, the plaintiff must prove that you directly benefited financially from the infringement, that you had the right or ability to supervise or control the infringement, and you failed to do so.

You say you are not benefiting financially from infringement by others which would defeat an argument for vicarious infringement, but "not benefiting financially" is broader than "doesn't charge the user" (ad revenue is a financial benefit, as relevant to Grokster). Even if you were benefiting financially, it's not obvious that you can control what others do with your software. The primary holding in Grokster is

that one who distributes a device with the object of promoting its use to infringe copyright, as shown by clear expression or other affirmative steps taken to foster infringement, is liable for the resulting acts of infringement by third parties

Grokster does not resolve a number of issues (which were raised in the concurring opinions) as to the role of non-infringing uses of software. We know that Grokster intended the software to be used to infringe copyright, we do not know whether your software has a non-infringing use. The court mentions the earlier finding that "distribution of a commercial product capable of substantial noninfringing uses could not give rise to contributory liability for infringement", which they don't reject and partially support saying

in the absence of other evidence of intent, a court would be unable to find contributory infringement liability merely based on a failure to take affirmative steps to prevent infringement, if the device otherwise was capable of substantial noninfringing uses. Such a holding would tread too close to the Sony safe harbor.


Aside from what user6726 discusses, there's also an issue when software basically exists to aid and abet a user's violation of Terms of Service. This is what gets all the MMO bot software in trouble. MMO makers have prevailed on claims of tortious interference, which means party A and party B have a contract (the ToS), and party C is interfering with their contract by tempting users to violate. Their success at applying tortious interference is notable because it's a very hard claim to prove, with 7 elements that all must be shown.

The only issue I can really see is if your software enables people who don't own a copy of the game to just download an illegal copy off BitTorrent etc. Then, you may be seen as abetting copyright infringement.

Well, if it is a server based game such as an MMO - if you wanted to create a "private server" for, say, Tabula Rasa -that might be legally complicated.

  • Recent case: Bungoe vs... some Noth European people selling a wall hack for destiny. It was RICO even.
    – Trish
    Commented May 21, 2023 at 10:55
  • @Trish It was also a default judgement, so take it with a grain of salt. Commented Jun 5, 2023 at 18:15

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