Tamper means to:

1. Touch or change something without permission or without enough knowledge of how it works. ^{cambridge.org 1}
2. Meddle, especially for the purpose of altering, damaging, or misusing. ^{dictionary.com 2}
3. Interfere in a harmful or disruptive manner, or make alterations secretly to subvert an intended purpose or function. ^{thefreedictionary.com 3}