Last week, Trustico (a reseller, formerly for Symantec and now for Comodo)
sent 23,000 private keys to DigiCert, to force their revocation. This
showed that Trustico had been storing customer keys generated through one
or more CSR/key generation forms on their website.
Though Trustico disagrees, this appears to be a clear case of routine key
compromise for subscribers who obtained their key from Trustico. The
security of Trustico's systems, which are not audited or accountable to
root program requirements, were storing large amounts of key material whose
compromise could have led to the subsequent compromise of connections to
tens of thousands of online services.
It was also noted that Trustico was exposing key material to interception
that Trustico's website had functionality that allowed remote code
execution as root on one of their web servers.
These m.d.s.p threads document/link to those things:
As part of the second thread, Comodo noted:
We also asked Trustico to cease offering any tools to generate and/or
retain customer private keys. They have complied with this request and
have confirmed that they do not intend to offer any such tools again in the
That is good to hear, but a "we won't do it again" response, if accepted by
Comodo as sufficient, seems disproportionate to the severity of the issue,
given Trustico's unfamiliarity with norms around private key management,
and with basic security practices.
It's also clear from the experience that rules of the road for resellers
are unclear, and that accountability is limited. It seems possible, or
likely, that other resellers may also be mishandling customer keys
So, what would useful next steps be to improve security and accountability
One thought: Mozilla could ask CAs to obtain a written response from all
contracted resellers about if/how they interact with customer key material,
including the level of isolation/security given their key generation
given access to generated key material.
Any other ideas?
Also -- Comodo noted:
Trustico have also confirmed to us that they were not, and are not, in
possession of the private keys that correspond to any of the certificates
that they have requested for their customers through Comodo CA.
Since there appears to have been a significant overlap period, between the
time Trustico switched to Comodo and when Trustico was asked by Comodo to
cease key storage practices, it's a little hard to take at face value the
assurance that Trustico was never in possession of any Comodo keys. It
would be nice to hear something from Comodo about whether they've verified
this in any more detail.
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