Could you expand on how xz took advantage of the dynamic loader (I think that's why you most likely meant)?
If you built your binary statically against the compromised version of xz, you'd still suffer wouldn't you? Or did it depend on dynamic linking in some way? I'm not really that familiar with the mechanism it used, so sorry if that's a basic question.
So, eg an entire distro built statically would still have been fully compromised. And without dynamic libs, you wouldn't be able to just update the single lib, you'd have to update everything. So to the extent your own software is statically linked, your own software may be fine (because you never picked up the new update) but you are still vulnerable if the statically linked system had the bad lib linked in.
The xz hack used an ifunc resolver to load its payload, where the ifunc resolver is a function that the dynamic loader calls to figure out what the address of a symbol should be (i.e., to make something dependent on the current hardware capabilities).
If you built your binary statically against the compromised version of xz, you'd still suffer wouldn't you? Or did it depend on dynamic linking in some way? I'm not really that familiar with the mechanism it used, so sorry if that's a basic question.
So, eg an entire distro built statically would still have been fully compromised. And without dynamic libs, you wouldn't be able to just update the single lib, you'd have to update everything. So to the extent your own software is statically linked, your own software may be fine (because you never picked up the new update) but you are still vulnerable if the statically linked system had the bad lib linked in.