Blunder by Trustico revokes 23,000 website certificates

March hasn't got off to the best start for 23,000 customers of HTTPS certificate reseller Trustico.

Based in the UK, Trustico touts SSL/TLS certificates that are used by websites to encrypt and secure their connections. The company resells certs from the Symantec umbrella (now owned and operated by DigiCert) which included GeoTrust, Thawte, and Rapid SSL.

Essentially the company sells the reassuring green padlock in the corner of users' browsers, which illustrates the HTTPS cert that leads back along a chain of trust to DigiCert.

The aforementioned customers recently received an email informing them their website security certificates will be rendered useless within 24 hours.

The case is ongoing with no perfect clarity yet, but the most common report is Trustico allegedly made an epic blunder in sending the private keys for said certificates in an email.

These keys are supposed to be secret with the only holders of their details to be the owners – and certainly not disclosed via email as in the wrong hands they can be used by cybercriminals to masquerade malicious websites as legitimate.

What this means for the affected customers is unless they replace their certificates then visitors to their sites will be turned away due to the digital certificates being revoked.

DigiCert chief product officer Jeremy Rowley wrote in an email to a public security list that Trustico told Digicert in early February that its resold certificates had been in some way compromised, and thus needed to be revoked.

The staff at DigiCert then asked for more information regarding the 'compromise' to which the reseller replied saying it had a copy of the private keys, a grounds for mass revocation.

Before acting on this bombshell, DigiCert asked for evidence to which Trustico simply replied via email with 23,000 certificate keys. DigiCert then had no option but to act by the rulebook and revoke all the Trustico-sold certificates within 24 hours.

"Trustico has not provided any information about how these certificates were compromised or how they acquired the private keys," explained Rowley.

"As is standard practice for a Certificate Authority, DigiCert never had possession of these private keys. Currently, we are only revoking the certificates if we received the private keys. There are additional certificates the reseller requested to have revoked, but DigiCert has decided to disregard that request until we receive proof of compromise or more information about the cause of this incident."

Rowley continued the conversation on Twitter : "I'll likely be posting the private keys later once people have a fair chance to replace their certificates ... The allegation of compromise, keys compromised, and request for revocation all came from Trustico."

By doing this, Rowley hopes to disclose self-sign certificates produced using the private keys while will effectively prove that the classified details were sent to DigiCert without revealing the actual information in public – some have already emerged online.

Following the obligation to take action, DigiCert's RapidSSL business fired out email alerts to Trustico customers stressing the need to get new HTTPS certificates – or watch their sites go down.

Venafi senior technical manager Nick Hunter says this whole fiasco simply shouldn't have happened.

"Bad things are more likely to happen anytime organisation allows a third party to manage their private keys," says Hunter.

"Organisations need to perform immediate risk assessments of their key and certificate management program, from issuance to revocation – and this incident proves why. The only way to protect yourself from these kinds of situations is to control key generation yourself using an automated, centralized key management solution.