To be honest, liblzma using systemd seems like an unimportant detail more than anything else. On my laptop there's 141 binaries in /bin/ that link against lzma

To be honest, liblzma using systemd seems like an unimportant detail more than anything else. On my laptop there's 141 binaries in /bin/ that link against lzma; an abbreviated list with similar entries omitted below. And that's a fairly minimal Void Linux system – the list for an average Ubuntu system is probably a lot longer. Sneaking in via kmod, grub-install, udevd, or xbps-install seems just as viable as sneaking in via libsystemd. Perhaps a little bit harder, but not much. It will remain problem as long as you have a single command that runs your malicious code as root. Being directly linked against sshd was convenient, but there's all sorts of devious shit you can pull once you've got root, and it doesn't take that much more effort. % for f in /bin/*(*); ldd $f 2>&1 | grep -q lzma && print $f /bin/amdgpu-arch /bin/bsdcat /bin/bsdcpio /bin/bsdtar /bin/bsdunzip /bin/c-index-test /bin/clang-* /bin/clangd /bin/diagtool /bin/ffmpeg /bin/ffplay /bin/ffprobe /bin/find-all-symbols /bin/grub-editenv /bin/grub-install /bin/grub-mkimage /bin/grub-mknetdir /bin/grub-mkrescue /bin/grub-mkstandalone /bin/kmod /bin/lspci /bin/modularize /bin/mpv /bin/nvptx-arch /bin/pp-trace /bin/pskctool /bin/qemu-* /bin/rtorrent /bin/tiffcp /bin/tiffdump /bin/tiffinfo /bin/tiffset /bin/tiffsplit /bin/udevadm /bin/udevd /bin/update-mime-database /bin/xbps-alternatives /bin/xbps-checkvers /bin/xbps-create /bin/xbps-dgraph /bin/xbps-digest /bin/xbps-fbulk /bin/xbps-fetch /bin/xbps-install /bin/xbps-pkgdb /bin/xbps-query /bin/xbps-reconfigure /bin/xbps-remove /bin/xbps-rindex /bin/xbps-uchroot /bin/xbps-uhelper /bin/xbps-uunshare /bin/xmlcatalog /bin/xmllint /bin/xsltproc /bin/zstd