What is the ruling of Islam on adopting an abandoned child and changing his name to align with the family name to protect him from society?

Adoption, which is the attribution of a child to someone other than their biological father, is impermissible. Islam has nullified this practice, as Allah Almighty says: "Call them by [the names of] their fathers; it is more just in the sight of Allah." This is because it entails many prohibitions, including: private seclusion (khalwa) and handshakes between the adopted child and those who are not their lawful mahram, issues of inheritance, the mixing of lineages, and the loss of rights. Therefore, it is not permissible to name the child after the family of their guardian. However, they must be protected from bad customs, and there is a great reward for them in doing so.