A decision that Apple made unilaterally in February 2020 has impacted the entire browser landscape and has effectively bolstered the Certification Authority industry to bitterly accept a new default lifetime of 398 days for TLS certificates.
Following Apple’s initial announcement, Mozilla and Google have stated similar intentions to implement the same rule in their browsers.
Starting September 1, 2020, browsers and devices from Apple, Google and Mozilla will show errors for new TLS certificates that have a lifespan of more than 398 days.
The CA / B forum and the useful life of TLS
The move is important because it not only changes the way a central part of the Internet, TLS certificates, works, but also because it separates from normal industry practices and cooperation between browsers and CAs.
Known as the CA / B Forum, this is an informal group comprised of Certification Authorities (CAs), companies that issue TLS certificates used to support HTTPS traffic, and browser manufacturers.
Since 2005, this group has been setting the rules on how TLS certificates should be issued and how browsers are supposed to manage and validate them.
Browsers and CAs generally discussed the next rules until they reached common ground, and then approved the rules that all members implemented.
However, throughout its 15-year history, there has been an issue that has always altered pens every time it has been mentioned, and that is the lifespan of TLS certificates.
TLS’s lifespan started at eight years, and over the years, browser manufacturers have reduced it, reducing it to five, then three, and then two.
The previous change came in March 2018, when browser makers tried to reduce the lifespan of SSL certificates from three to one, but were compromised for two years after an aggressive rejection by CAs.
But barely a year has passed since they reduced TLS’s lifespan from three to two years, and browser makers tried again, to the dismay of CAs, which, at the time, thought they made a compromise and raised the issue. to the bed.
As ZDNet reported last summer, browser providers again attempted to reduce the lifespan of TLS certificates from two to one year. Voting on this proposal, called by Google, failed in September 2019. While the proposal garnered 100% support from browser manufacturers, only 35% of CAs voted to approve a TLS certificate lifetime of a year.
Browser Providers Override CA / B Forum
But in February, Apple broke the CA / B Forum standard operating procedure. Instead of asking for a vote, Apple simply announced its decision to implement 398 days of shelf life on its devices, regardless of what CAs thought at the CA Forum. / B on the subject.
Two weeks later, Mozilla announced the same, and earlier this month, Google also made a similar announcement.
Chrome teams up with Apple to limit public TLS certificates to 398 days from September 1.
– Dean Coclin (@chosensecurity) June 10, 2020
What happened this year is, in simple words, a demonstration that browser manufacturers control the CA / B Forum, and that they have full control of the HTTPS ecosystem, and that CAs are merely participants with no real power.
What happened this year was also predicted by HashedOut, a friendly CA news site dedicated to the CA industry.
“If CAs vote this measure down [the September 2019 ballot], there is a possibility that browsers could act unilaterally and force change anyway, “the site wrote in August 2019, a month before the vote.
“That is unprecedented, but it has never happened on an issue that is traditionally as collegial as this,” he added. “If it does, it’s fair to ask what the point of the CA / B Forum is. Because at that point, browsers would basically be ruling by decree and the entire exercise would be a sham.”
Why were browser providers so concerned with shorter TLS certificates?
To strangers, this all seems like a silly drama about technicalities and a work of power. However, there is a reason why browser manufacturers have been pushing for shorter TLS certificates.
The main reason is that the wrong TLS certificates are removed more quickly.
The rule is that once a TLS certificate has been abused by malware, phishing, or other operations, CAs must revoke the certificate.
However, in practice, the certificate revocation process has been a disaster for years, with very few CAs revoking certificates on time and the wrong certificates still valid for years, allowing bad guys to use and reuse the same certificate for multiple operations.
Browser manufacturers argued that by reducing the lifespan of the TLS certificate, these certificates would become invalid faster, even if they were issued by AC slack.
In addition, there is also the issue of traffic decryption. At some point in the future, browser manufacturers anticipate that threat actors will be able to decrypt the HTTPS traffic they are recording today.
By securing traffic with shorter certificates, browser manufacturers expect this process to require more resources for attackers.
CAs have been struggling with shorter lifespan because they believe that none of these issues really makes a difference, as malware operations tend to abandon TLS certificates after using them once, especially now because many companies offer free TLS certificates. under various offers and programs.
Shorter life spans only create more work for your IT teams and change industry standards that they believe should remain unchanged, as this is how standards are supposed to work, staying the same, not being updated every year.
However, the problem has been decided, and the CAs are not entirely satisfied with how the whole process went. At a May 2020 meeting of the CA / B Forum, some CAs provided public responses to Apple’s decision, and many did not have a positive tone.
Actalis said “whether they like it or not” they “are bound to comply.”
D-TRUST, another CA, said it was also forced to comply with this new TLS lifetime, but made it clear that they saw “no security gain or other benefits in shortening the lifetime of the certificate.”
Telia described the whole thing as “an unnecessary burden on our community.”
And the responses continue, in the same passive-aggressive tone of “yes, we will, but we are not happy with that.”
What does this mean after September 1, 2020?
For the certification authorities: If you want the TLS certificates that you issue after this date to be recognized in the Apple, Google, and Mozilla browsers, the certificates must not have a lifespan that exceeds 398 days or the certificate will issue an error and connections will be cut.
For website owners: They will have to renew TLS certificates annually, instead of two years.
For end users: They may see more HTTPS errors in their browsers.
