Frontier is an Ethereum compatibility layer for Substrate. Frontier's `modexp` precompile uses `num-bigint` crate under the hood. In the implementation prior to pull request 1017, the cases for modulus being even and modulus being odd are treated separately. Odd modulus uses the fast Montgomery multiplication, and even modulus uses the slow plain power algorithm. This gas cost discrepancy was not accounted for in the `modexp` precompile, leading to possible denial of service attacks.
No fixes for `num-bigint` are currently available, and thus this issue is fixed in the short term by raising the gas costs for even modulus, and in the long term fixing it in `num-bigint` or switching to another modexp implementation. The short-term fix for Frontier is deployed at pull request 1017. There are no known workarounds aside from applying the fix.
References
History
No history.
MITRE Information
Status: PUBLISHED
Assigner: GitHub_M
Published: 2023-03-22T20:11:43.772Z
Updated: 2023-03-22T20:11:43.772Z
Reserved: 2023-03-15T15:59:10.051Z
Link: CVE-2023-28431
JSON object: View
NVD Information
Status : Modified
Published: 2023-03-22T21:15:18.170
Modified: 2023-11-07T04:10:35.300
Link: CVE-2023-28431
JSON object: View
Redhat Information
No data.
CWE