The eMudhra certification authority has revoked another 8 intermediate root certificates

eMudhra has revealed additional details regarding the incident in which eight root certificates from the certificate authority had easily guessable private keys with only 1 byte of entropy instead of 48. In addition to the initially identified problematic intermediate root certificates, another 8 have been revoked, but not due to entropy issues. The analysis indicated that the source of the entropy problems was a self-created Python script used for transferring private keys between hardware security modules (HSM) from different manufacturers. The key transfer was necessitated by delays in the delivery of upgraded HSM models that meet the new requirements for certificate authorities.

Due to an error, the size of the ECDSA private keys was truncated to 1 byte. In addition, during the transfer of keys between HSMs, the script processed private keys in the unsecured RAM of the computer on which it was running, whereas operations with private keys should only be conducted within the HSM. HSM logs confirmed that the hardware storage was functioning correctly and that the issue was caused by the use of the homemade script.

In addition to ECDSA keys, the script was also used for transferring 8 RSA-4096 keys, which did not encounter entropy issues, but processing keys in regular memory violates the security requirements imposed on certificate authorities, so RSA certificates have also been revoked.

Source: opennet.ru