Impact Metadadata signature verification, as used in tuf.client.updater, counted each of multiple signatures with identical authorized keyids separately towards the threshold. Therefore, an attacker with access to a valid signing key could create multiple valid signatures in order to meet the minimum threshold of keys before the metadata was considered valid.
The tuf maintainers would like to thank Erik MacLean of Analog Devices, Inc. for reporting this issue.
Patches A fix is available in version 0.12.2 or newer.
Workarounds No workarounds are known for this issue.
References CVE-2020-6174 Pull request resolving the issue PR 974
Impact An attacker who can gain file access to the repository and modify metadata files may cause a denial of service to clients by creating many invalid signatures on a metadata file. Having a large number of signatures to verify will delay the moment when the client will determine the signature is not valid. This delay may be for at least a few minutes, but possibly could be longer especially if multiple files are impacted.
The tuf maintainers would like to thank Erik MacLean of Analog Devices, Inc. for reporting this issue.
Patches No fix exists for this issue.
Workarounds No workarounds are known for this issue.
References CVE-2020-6173 Issue #973