On Sat, Apr 18, 2020 at 10:59:51AM -0400, Wietse Venema wrote: > Rich Felker: > > > It would be a mistake to use TLSA records from an unsigned domain. > > > That would be no more secure than accepting a random server > > > certificate. All the pain of doing TLSA and none of the gain, just > > > security theatre. > > > > It's not security theater. It (1) ensures that you do use records for > > a signed domain even if you were unable to determine it was signed, > > due to issues like lack of AD bit in musl or stripping of AD bit by > > glibc default configuration, and (2) makes it so an attacker wanting > > to MITM needs to be able to do so on DNS channel, not just route to > > the MX. (For example this might be difficult or impossible for the > > attacker if DNS is routed over DoH, or if attacker can sit somewhere > > between client and MX but not between client and the nearest anycast > > 8.8.8.8.) > > Congratulations! You just gave a new definition of security theatre: > using an unauthenticated channel to distribute trust anchors.
It's not security theater because nobody's claiming it's secure. Rather it's a fairly weak form of hardening that increases the required capabilities an attacker needs to exploit a known-insecure system. > You can consider libc-musl as unsupported from now on. I am really not appreciating the hostility and utterly petty vindictiveness of folks from this project. Rich
