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Drainage of FeeCollector's Block Transaction Fees in cronos

High severity GitHub Reviewed Published Dec 21, 2021 in crypto-org-chain/cronos • Updated Feb 3, 2023

Package

gomod github.com/crypto-org-chain/cronos (Go)

Affected versions

< 0.6.5

Patched versions

0.6.5
gomod github.com/tharsis/ethermint (Go)
>= 0.8.0, < 0.10.0
< 0.7.3
0.10.0
0.7.3
gomod github.com/tharsis/evmos (Go)
<= 0.4.2
None

Description

Impact

In Cronos nodes running versions before v0.6.5, it is possible to take transaction fees from Cosmos SDK's FeeCollector for the current block by sending a custom crafted MsgEthereumTx.

User funds and balances are safe.

Patches

This problem has been patched in Cronos v0.6.5 on the mempool level.
The next network upgrade with consensus-breaking changes will patch it on the consensus level.

Workarounds

There are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience.

Credits

Thank you to @zb3 for reporting this issue on Cronos Immunefi Bug Bounty Program, to @cyril-crypto for reproducing the issue and to @yihuang and @thomas-nguy for patching the issue on the CheckTx (mempool) and the DeliverTx (consensus) levels.

For more information

If you have any questions or comments about this advisory:

References

@tomtau tomtau published to crypto-org-chain/cronos Dec 21, 2021
Published by the National Vulnerability Database Dec 21, 2021
Reviewed Jan 4, 2022
Published to the GitHub Advisory Database Jan 6, 2022
Last updated Feb 3, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS score

0.112%
(46th percentile)

Weaknesses

CVE ID

CVE-2021-43839

GHSA ID

GHSA-f854-hpxv-cw9r

Source code

Credits

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