Cosmos SDK: Groups module can halt chain when handling a malicious proposal

Summary

Name: ASA-2025-003: Groups module can halt chain when handling a malicious proposal Component: CosmosSDK Criticality: High (Considerable Impact; Likely Likelihood per [ACMv1.2](https://github.com/interchainio/security/blob/main/resources/CLASSIFICATION_MATRIX.md)) Affected versions: <= v0.47.15, <= 0.50.11 Affected users: Validators, Full nodes, Users on chains that utilize the groups module ### Description An issue was discovered in the groups module where a malicious proposal would result in a division by zero, and subsequently halt a chain due to the resulting error. Any user that can interact with the groups module can introduce this state. ### Patches The new Cosmos SDK release [v0.50.12](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.50.12) and [v0.47.16](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.47.16) fix this issue. ### Workarounds There are no known workarounds for this issue. It is advised that chains apply the update. ### Timeline * February 9, 2025, 5:18pm PST: Issue reported to the Cosmos Bug Bounty program * February 9, 2025, 8:12am PST: Issue triaged by Amulet on-call, and distributed to Core team * February 9, 2025, 12:25pm PST: Core team completes validation of issue * February 18, 2025, 8:00am PST / 17:00 CET: Pre-notification delivered * February 20, 2025, 8:00am PST / 17:00 CET: Patch made available This issue was reported to the Cosmos Bug Bounty Program by [dongsam](https://github.com/dongsam) on HackerOne on February 9, 2025. If you believe you have found a bug in the Interchain Stack or would like to contribute to the program by reporting a bug, please see https://hackerone.com/cosmos. If you have questions about Interchain security efforts, please reach out to our official communication channel at [[email protected]](mailto:[email protected]). For more information about the Interchain Foundation’s engagement with Amulet, and to sign up for security notification emails, please see https://github.com/interchainio/security. A Github Security Advisory for this issue is available in the Cosmos SDK [repository](https://github.com/cosmos/cosmos-sdk/security/advisories/GHSA-x5vx-95h7-rv4p).