Re: feedback requested regarding deprecation of TLS 1.0/1.1

[Jacob Bachmeyer <jcb62281 () gmail com>]

Clemens Lang wrote:
> > On 7. Aug 2024, at 19:48, Solar Designer <solar () openwall com> wrote:
> >
> > 1. Hosting a public server that's meant to be usable by the widest
> > audience possible, including from both up-to-date and older systems.
> > For example, a website should display in latest web browsers, but
> > command-line downloads from the same server should also work from old
> > systems (e.g., running LTS distros).
> >     
>
> Speaking of LTS distros: RHEL 6.10 supports TLS 1.2.
> At what point is a distro not LTS, but a museum piece which we can ignore?
> What currently supported LTS distro does not support TLS 1.2?
>   

Legacy is a long tail and there is a big difference between 
communications on the open Internet and support for archaic protocol 
versions to talk to older devices on a LAN.  Disabling support by 
default is one thing; removing it entirely is another and much more serious.

> > 2. Scanning or crawling a wide variety of systems, e.g. by a search
> > engine indexer, an asset enumeration tool, a security scanner, or during
> > a pentest.
> >     
>
> What good is a search engine index of a webpage no modern browser will connect to?
>   

A user may have an older browser around, the page may also be available 
via plain HTTP (very likely if the server is that old), or the search 
engine might offer a cached copy.  For a specific crawler that could 
have use for this scenario, consider the Internet Archive Wayback Machine.

> The other use cases sound like they’d be done with special tooling anyway, in which case that can continue to ship an 
> older version of OpenSSL for this purpose.

Presumably that "older version of OpenSSL" would be unmaintained, which 
means that it is likely to accumulate known exploits over time.  This 
could be *very* bad for an asset enumeration tool or security scanner 
that could encounter a malicious server that insists on an old protocol 
version in order to exploit that older library and crack the scanner host!


-- Jacob