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Sometimes you just have to take a stand. Apple apparently did just that at the CA/Browser (CA/B) Forum in Bratislava, Slovakia this week. While the company has not made a public announcement, it appears that starting September 1, 2020, Apple’s Safari browser will no longer trust TLS certificates with validity periods longer than one year (398 days). Ultimately, this move should strengthen the security of these machine identities.
Apple says 1-year validity periods for Safari
Last year, the CA/B Forum voted down a Google proposal to limit TLS certificate validity periods to one year. Many CAs were concerned that increasing the burden on their customers to rotate certificates more frequently was too great. But it’s still the right thing to do. So Apple chose a different route. By enforcing 1-year validity periods on its popular Safari browser, the company in essence makes 398-day certificates the de facto standard.
Essentially, what this means is that websites who want to be trusted by Safari, will no longer be able rely on publicly trusted TLS certificates with lifespans longer than 398 days after August 30, 2020. Of course, longer validity certificates issued before September 1, 2020 will remain valid until their expiration.
Why this is good
Shorter certificate lifespans are ultimately beneficial to security efforts. If a certificate is compromised in any way, a shorter validity means less time to be exploited. Security writer, Kim Crawley summed up the value of shorter validity periods in aprevious post. “Shorter time durations for HTTPS certificates sounds like a great idea to me. Sometimes certificates are breached. A certificate that lasts 13 months instead of 27 reduces the scope of data compromise when that happens.”
Kevin Bocek, vice president of security strategy and threat intelligence at Venafi notes:
“Apple’s decision to move to 398-day certificates affects nearly every digital business and is part of a larger trend toward shorter TLS certificate lifespans. Shorter certificate lifespans definitely improve security but because businesses are using more TLS certificates this shift will require companies to invest in automation or risk costly and painful certificate outages. This is especially critical for companies that are moving to the cloud.”
In another post, we highlighted Security consultant Scott Helme’s views on why shorter validity periods are a good thing:
- The Revocation Process Is "Completely Broken"
Because the process is cumbersome, they may not provide timely protection against certain hazardous situations, such as a stolen or exposed private key. Shorter validity periods mean less exposure.
- New Threats Are Constantly Challenging the Certificate Ecosystem
The certificate ecosystem is not static. It's constantly changing. One of the factors that drives this dynamism is the appearance of new threats. Shorter validity periods allow CAs and owners to stay on top of developments such as the weakening of SHA-1 with minimal need for unscheduled re-issuing.
- Private Keys Need More Frequent Rotation
By rotating their cryptographic keys, organizations can reduce the material encrypted with a single key, thereby minimizing the potential impact of a single key compromise. With shorter validity periods, enterprises can simply time the rotation of their keys with their certificates' expiration dates.
- Long Validity Periods Make Log Disqualification More Likely
Certificate Transparency (CT) requires all CAs to log their issued certificates into public and auditable logs. The problem is that certificate logs can disqualify during the lifetime of a certificate. The longer the validity period of a certificate, the greater the likelihood that a certificate could encounter a log disqualification.
What does this mean for web application owners?
As I mentioned before, the major objection to shorter certificate validity is the additional work required by web application teams to rotate certificates more frequently. Plus, more frequent expirations could increase the chances of certificate outages. Those concerns can be easily allayed by the use of a proper platform for machine identity management that would automate the renewal process and ultimately simplify the management of the entire certificate lifecycle.
“Browser makers have become much more active in determining which certificates are trusted,” concludes Kevin Bocek. “In addition to this move by Apple, Google recently required all CAs to post the certificates they issue to Google Transparency logs or they will not be trusted in Chrome. In light of these changes, every organization needs to take a hard look at the way they manage and protect the keys and certificates that serve as machine identities.”
Forward-thinking companies began to realize the value of centrally managing, and ultimately protecting, machine identities early on. Now, as a result of digital transformation, we’re seeing an increasing number of the world’s leading organizations getting serious about managing their machine identities.
Is your organization ready for shorter certificate validity periods?