tls

the-number-of-mis-issued-1111-certificates-grows-here’s-the-latest.

The number of mis-issued 1.1.1.1 certificates grows. Here’s the latest.

Cloudflare on Thursday acknowledged this failure, writing:

We failed three times. The first time because 1.1.1.1 is an IP certificate and our system failed to alert on these. The second time because even if we were to receive certificate issuance alerts, as any of our customers can, we did not implement sufficient filtering. With the sheer number of names and issuances we manage it has not been possible for us to keep up with manual reviews. Finally, because of this noisy monitoring, we did not enable alerting for all of our domains. We are addressing all three shortcomings.

Ultimately, the fault lies with Fina; however, given the fragility of the TLS PKI, it’s incumbent on all stakeholders to ensure system requirements are being met.

And what about Microsoft? Is it at fault, too?

There’s some controversy on this point, as I quickly learned on Wednesday from social media and Ars reader comments. Critics of Microsoft’s handling of this case say that, among other things, its responsibility for ensuring the security of its Root Certificate Program includes checking the transparency logs. Had it done so, critics said, the company would have found that Fina had never issued certificates for 1.1.1.1 and looked further into the matter.

Additionally, at least some of the certificates had non-compliant encoding and listed domain names with non-existent top-level domains. This certificate, for example, lists ssltest5 as its common name.

Instead, like the rest of the world, Microsoft learned of the certificates from an online discussion forum.

Some TLS experts I spoke to said it’s not within the scope of a root program to do continuous monitoring for these types of problems.

In any event, Microsoft said it’s in the process of making all certificates part of a disallow list.

Microsoft has also faced long-standing criticism that it’s too lenient in the requirements it imposes on CAs included in its Root Certificate Program. In fact, Microsoft and one other entity, the EU Trust Service, are the only ones that, by default, trust Fina. Google, Apple, and Mozilla don’t.

“The story here is less the 1.1.1.1 certificate and more why Microsoft trusts this carelessly operated CA,” Filippo Valsorda, a Web/PKI expert, said in an interview.

I asked Microsoft about all of this and have yet to receive a response.

The number of mis-issued 1.1.1.1 certificates grows. Here’s the latest. Read More »

google-calls-for-halting-use-of-whois-for-tls-domain-verifications

Google calls for halting use of WHOIS for TLS domain verifications

WHOWAS —

WHOIS data is unreliable. So why is it used in TLS certificate applications?

Google calls for halting use of WHOIS for TLS domain verifications

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Certificate authorities and browser makers are planning to end the use of WHOIS data verifying domain ownership following a report that demonstrated how threat actors could abuse the process to obtain fraudulently issued TLS certificates.

TLS certificates are the cryptographic credentials that underpin HTTPS connections, a critical component of online communications verifying that a server belongs to a trusted entity and encrypts all traffic passing between it and an end user. These credentials are issued by any one of hundreds of CAs (certificate authorities) to domain owners. The rules for how certificates are issued and the process for verifying the rightful owner of a domain are left to the CA/Browser Forum. One “base requirement rule” allows CAs to send an email to an address listed in the WHOIS record for the domain being applied for. When the receiver clicks an enclosed link, the certificate is automatically approved.

Non-trivial dependencies

Researchers from security firm watchTowr recently demonstrated how threat actors could abuse the rule to obtain fraudulently issued certificates for domains they didn’t own. The security failure resulted from a lack of uniform rules for determining the validity of sites claiming to provide official WHOIS records.

Specifically, watchTowr researchers were able to receive a verification link for any domain ending in .mobi, including ones they didn’t own. The researchers did this by deploying a fake WHOIS server and populating it with fake records. Creation of the fake server was possible because dotmobiregistry.net—the previous domain hosting the WHOIS server for .mobi domains—was allowed to expire after the server was relocated to a new domain. watchTowr researchers registered the domain, set up the imposter WHOIS server, and found that CAs continued to rely on it to verify ownership of .mobi domains.

The research didn’t escape the notice of the CA/Browser Forum (CAB Forum). On Monday, a member representing Google proposed ending the reliance on WHOIS data for domain ownership verification “in light of recent events where research from watchTowr Labs demonstrated how threat actors could exploit WHOIS to obtain fraudulently issued TLS certificates.”

The formal proposal calls for reliance on WHOIS data to “sunset” in early November. It establishes specifically that “CAs MUST NOT rely on WHOIS to identify Domain Contacts” and that “Effective November 1, 2024, validations using this [email verification] method MUST NOT rely on WHOIS to identify Domain Contact information.”

Since Monday’s submission, more than 50 follow-up comments have been posted. Many of the responses expressed support for the proposed change. Others have questioned the need for a change as proposed, given that the security failure watchTowr uncovered is known to affect only a single top-level domain.

An Amazon representative, meanwhile, noted that the company previously implemented a unilateral change in which the AWS Certificate Manager will fully transition away from reliance on WHOIS records. The representative told CAB Forum members that Google’s proposed deadline of November 1 may be too stringent.

“We got feedback from customers that for some this is a non-trivial dependency to remove,” the Amazon representative wrote. “It’s not uncommon for companies to have built automation on top of email validation. Based on the information we got I recommend a date of April 30, 2025.”

CA Digicert endorsed Amazon’s proposal to extend the deadline. Digicert went on to propose that instead of using WHOIS records, CAs instead use the WHOIS successor known as the Registration Data Access Protocol.

The proposed changes are formally in the discussion phase of deliberations. It’s unclear when formal voting on the change will begin.

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