'This year Let's Encrypt announced that it's issued a billion
certificates, and it's been estimated they've made certs for almost
30% of web domains. But Friday they posted that "The DST Root X3 root
certificate that we relied on to get us off the ground is going to
expire — on September 1, 2021. Fortunately, we're ready to stand on
our own, and rely solely on our own root certificate."
"However, this does introduce some compatibility woes."
Some software that hasn't been updated since 2016 (approximately when
our root was accepted to many root programs) still doesn't trust our
root certificate, ISRG Root X1. Most notably, this includes versions
of Android prior to 7.1.1. That means those older versions of Android
will no longer trust certificates issued by Let's Encrypt.
Android has a long-standing and well known issue with operating system
updates. There are lots of Android devices in the world running
out-of-date operating systems. The causes are complex and hard to fix:
for each phone, the core Android operating system is commonly modified
by both the manufacturer and a mobile carrier before an end-user
receives it. When there's an update to Android, both the manufacturer
and the mobile carrier have to incorporate those changes into their
customized version before sending it out. Often manufacturers decide
that's not worth the effort. The result is bad for the people who buy
these devices: many are stuck on operating systems that are years out
Currently, 66.2% of Android devices are running version 7.1 or above.
The remaining 33.8% of Android devices will eventually start getting
certificate errors when users visit sites that have a Let's Encrypt
certificate. In our communications with large integrators, we have
found that this represents around 1-5% of traffic to their sites.
Hopefully these numbers will be lower by the time DST Root X3 expires
next year, but the change may not be very significant.
Let's Encrypt engineer Jacob Hoffman-Andrews explains that "In the
time between now and September 29 we plan to start serving
certificates with the 'alternate' link relation 186 to allow Automatic
Certificate Management Environment (ACME) clients to programmatically
select a chain they prefer." But Friday's blog post explains that
won't solve everything:
There will be site owners that receive complaints from users and we
are empathetic to that being not ideal. We're working hard to alert
site owners so you can plan and prepare. We encourage site owners to
deploy a temporary fix (switching to the alternate certificate chain)
to keep your site working while you evaluate what you need for a
long-term solution: whether you need to run a banner asking your
Android users on older OSes to install Firefox, stop supporting older
Android versions, drop back to HTTP for older Android versions, or
switch to a CA that is installed on those older versions.
Gizmodo notes that Firefox will be unaffected "since it relies on its
own certificate store that includes Let's Encrypt's root, though that
wouldn't keep applications from breaking or ensure functionality
beyond your browser." They describe Let's Encrypt as "the
Mozilla-partnered nonprofit," and offers this succinct summary of the
"One of the world's top certificate authorities warns that phones
running versions of Android prior to 7.1.1 Nougat will be cut off from
large portions of the secure web starting in 2021."'
-- source: https://it.slashdot.org/story/20/11/08/1654223
Dept. of Computer Science
University of Waikato, NZ
+64 (7) 577-5304