CVE-2021-41135 Cosmos-SDK up to 0.44.1 xauthz Module ValidateBasic unusual condition (21st Oct, 2021)

Preface:To date, more than 240 applications have been built on the Cosmos mainnet. The main categories of applications include finance, infrastructure, privacy, and social interactions.

Background: The Cosmos SDK is a framework for building blockchain applications. Tendermint Core (BFT Consensus) and the Cosmos SDK are written in the Golang programming language. Cosmos SDK is used to build Gaia, the first implementation of the Cosmos Hub.

Vulnerability details: Affected versions of the SDK (up to 0.44.1) were vulnerable to a consensus halt due to non-deterministic behaviour in a ValidateBasic method in the x/authz module. The MsgGrant of the x/authz module contains a Grant field which includes a user-defined expiration time for when the authorization grant expires. In Grant.ValidateBasic(), that time is compared to the node’s local clock time. Any chain running an affected version of the SDK with the authz module enabled could be halted by anyone with the ability to send transactions on that chain. Recovery would require applying the patch and rolling back the latest block. Users are advised to update to version 0.44.2.

Remedy: Upgrading to version 0.44.2 eliminates this vulnerability. Applying the patch 68ab790a761e80d3674f821794cf18ccbfed45ee is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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