Signers can backdoor the safe to execute any transaction in the future without consensus
The function `checkAfterExecution()` is called by the safe after signer's request TX was executed (and authorized). It mainly checks that the linkage between the safe and the HSG has not been compromised.\\n```\\n        function checkAfterExecution(bytes32, bool) external override {\\n            if (abi.decode(StorageAccessible(address(safe)).getStorageAt(uint256(GUARD_STORAGE_SLOT), 1), (address))\\n                    != address(this)) \\n                    {\\n                revert CannotDisableThisGuard(address(this));\\n            }\\n            if (!IAvatar(address(safe)).isModuleEnabled(address(this))) {\\n                    revert CannotDisableProtectedModules(address(this));\\n            }\\n            if (safe.getThreshold() != _correctThreshold()) {\\n                     revert SignersCannotChangeThreshold();\\n            }\\n            // leave checked to catch underflows triggered by re-erntry\\n        attempts\\n            --guardEntries;\\n        }\\n```\\n\\nHowever, it is missing a check that no new modules have been introduced to the safe. When modules execute TXs on a Gnosis safe, the guard safety callbacks do not get called. As a result, any new module introduced is free to execute whatever it wishes on the safe. It constitutes a serious backdoor threat and undermines the HSG security model.
Check that no new modules have been introduced to the safe, using the `getModulesPaginated()` utility.
```\\n        function checkAfterExecution(bytes32, bool) external override {\\n            if (abi.decode(StorageAccessible(address(safe)).getStorageAt(uint256(GUARD_STORAGE_SLOT), 1), (address))\\n                    != address(this)) \\n                    {\\n                revert CannotDisableThisGuard(address(this));\\n            }\\n            if (!IAvatar(address(safe)).isModuleEnabled(address(this))) {\\n                    revert CannotDisableProtectedModules(address(this));\\n            }\\n            if (safe.getThreshold() != _correctThreshold()) {\\n                     revert SignersCannotChangeThreshold();\\n            }\\n            // leave checked to catch underflows triggered by re-erntry\\n        attempts\\n            --guardEntries;\\n        }\\n```\\n