After updating the root certificate signature algorithm from SHA1 to SHA2, the following error occurs during the stage2 pre-check of the upgrade vCenter Server from 7.0 to 8.0.
Error Support for certificates with weak signature algorithms has been removed in vCenter Server 8.0. The certificate with subject '/DC=###/CN=###/...' in VECS store TRUSTED_ROOTS has weak signature algorithm sha1WithRSAEncryption.
Resolution Replace the certificate with subject '/DC=###/CN=###/...' in VECS store TRUSTED_ROOTS with a certificate that uses the SHA-2 signature algorithm. Caution: Verify that any certificates signed by the problematic certificate are not in use by vCenter Server. Refer to the vCenter Server release notes and VMware KB 89424 for more details.
You can see similar to the following result by running vsphere8_upgrade_certificate_checks.py of KB 313460.
YYYY-MM-DD hh:mm:ss.fffZ ERROR #################### Errors Found ####################
YYYY-MM-DD hh:mm:ss.fffZ ERROR
YYYY-MM-DD hh:mm:ss.fffZ ERROR Support for certificates with weak signature algorithms has been removed in vSphere 8.0. Weak signature algorithm certificates must be replaced before upgrade. Refer to the vSphere release notes and VMware KB 89424 for more details. Correct the following 1 issues before proceeding with upgrade.
YYYY-MM-DD hh:mm:ss.fffZ ERROR
YYYY-MM-DD hh:mm:ss.fffZ ERROR 1. The certificate with subject '/DC=###/CN=###/...' in VECS store TRUSTED_ROOTS has weak signature algorithm sha1WithRSAEncryption. The certificate thumbprint is ##:##:...##:##. The certificate Subject Key Identifier is ##:##:...##:##. Caution: Verify that any certificates signed by the problematic certificate are not in use by vCenter Server.
YYYY-MM-DD hh:mm:ss.fffZ ERROR
YYYY-MM-DD hh:mm:ss.fffZ ERROR ######################################################
vCenter Server 8.0.x
Even after updating the signature algorithm to SHA2, the root certificate for the SHA1 signature algorithm remained.
vCenter Server 8.0.x does not support the SHA1 signature algorithm.
Remove root certificates of SHA1 signature algorithm using vCert.py.
To remove root certificates of SHA1 signature algorithm, please see the steps below.