Malicious Implementation Contract

A malicious implementation contract is a threat where an attacker manages to replace the legitimate logic contract of a proxy with their own malicious code. This is usually achieved by exploiting an insecure upgrade function or gaining administrative control.

Once the proxy points to the malicious contract, every function call made to the proxy executes the attacker's code. This grants the attacker full control over the protocol's assets and state.

It is the ultimate form of privilege escalation in upgradeable systems.