GebProxyActions Contract Flaw Leads to 5.9436 ETH Loss

A vulnerability in the GebProxyActions contract led to a loss of about 5.9436 ETH after the contract lacked caller access controls. According to ChainCatcher, the victim had previously called GebProxyActions.quitSystem directly instead of through a DSProxy delegate call, which caused ownsSAFE[safe] to be set to the GebProxyActions contract. The attacker then called GebProxyActions.quitSystem(manager, safe, dst) directly, bypassing GebSafeManager's safeAllowed check and transferring the collateral to themselves.