GHSA-v6rw-hhgg-wc4x: Evmos vulnerable to DOS and transaction fee expropiation through Authz exploit

Should you act?

• Only if you depend on one of the packages below, directly or transitively, in a vulnerable version. Check your lockfile with govulncheck ./....
• No CVE has been assigned, so it will not appear in CVE-based scanners that ignore GitHub advisories. npm audit, pip-audit and Dependabot do read GitHub advisories.

Affected packages

Details

Impact What kind of vulnerability is it? Who is impacted?

An attacker can use this bug to bypass the block gas limit and gas payment completely to perform a full Denial-of-Service against the chain.

Disclosure

Evmos versions below v11.0.1 do not check for MsgEthereumTx messages that are nested under other messages. This allows a malicious actor to perform EVM transactions that do not meet the checks performed under newEthAnteHandler. This opens the possibility for the DOS of validators and consequently halt the chain through an infinite EVM execution.

Additional details

The attack scenario is as follows:

1. The attacker deploys a simple smart contract with an infinite loop to the chain. 2. The attacker calls the smart contract using an embedded transaction with an extremely high gas value (uint64 max or similar). 3. Once the transaction is included in a block, nodes will try to execute the EVM transaction with almost infinite gas and get stuck. This stops new block creation and effectively halts the chain, requiring a manual restart of all nodes.

Users Impacted All Evmos users are impacted by this vulnerability as it has the potential to halt the chain. Users' funds and chain state are safe but when under attack, the chain could be deemed unusable.

CVSS: 9.1 (v3.1) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Sources and references

1. GitHub Advisory GHSA-v6rw-hhgg-wc4x github.com
2. github.com github.com

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