Many software packages come with a EULA which uses claims such as "by opening this package you hereby agree to ... (some laws going far beyond classical copyright)".

Now, what happens if your friend opens the package and installs it on his computer, and I would use the software not in a way permitted by the EULA.

For example, I decompile someone's code which they prohibit by EULA.

Under what grounds can I be sued? I never agreed to the EULA so it's not contract violation.

2 Answers 2


It's a contract violation if you're under the EULA. It may be a contract of adhesion, but such "clickwrap" contracts been found to be acceptable and enforceable in software EULAs out of necessity. However, there may be some limits.

If you're not under the EULA, as you argue, then you lack a license to use the software at all and it's an outright copyright violation and/or a theft or misappropriation of the software.

Whether or not you can be sued depends in part on what you do with it — if you don't release the material or otherwise cause damages then there's not much to sue for...

Added for clarification: to answer the framing question, supposing neither contract or copyright applied, one could be sued in tort or in equity (i.e. for unjust enrichment).

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    IIRC, it's definitely not certain that you need a license to use software in the US (the right to use isn't one of the enumerated exclusive rights of copyright, and US law has an exemption to copyright for any modifications and copies made as a necessary part of running a program on a computer (like copying the contents to RAM)).
    – cpast
    Commented Jul 20, 2015 at 16:36
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    I doubt most software companies would agree with that analysis.
    – daffy
    Commented Jul 20, 2015 at 20:12
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    Software companies don't actually decide copyright law. This is why they are so insistent that no one "owns" a copy of the software, and that the ownership of the copy is still held by the software company: because the owner of a copy of software has a right to use that software, under US copyright law.
    – cpast
    Commented Jul 20, 2015 at 20:23
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    And courts 'don't actually' file lawsuits. Plaintiffs do. The the courts decide them by applying the controlling authority . (Cert denied.) There are reasons to dislike the current state of the law, but the courts agree that licensed software is not sold and so not transferable under the first sale doctrine. So how do you not need a license to use licensed SW?
    – daffy
    Commented Jul 22, 2015 at 1:41
  • As to the idea that it's only the licensee that could be liable for the unlicensed use under copyright or contract, and not the unlicensed user, if the courts agreed there are other claims that could be asserted instead. Like misappropriation, or restitution of unjust enrichment (you enjoyed the utility of the software without paying for it), theft of trade secrets (in the case of the decompilation) etc. As mentioned in my answer.
    – daffy
    Commented Jul 22, 2015 at 2:35

Under the circumstances you describe, the friend who installed the software is unambiguously subject to the EULA.

The EULA presumably includes a provision prohibiting your friend from letting you use it, much less reverse engineer it.

Therefore, your friend is in violation of the license agreement and will be liable for any resulting damages. If you caused the damage, you may, depending on the circumstances, be liable in turn to indemnify your friend for the damages.

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