In systemd 240, busopensystemwatchbindwithdescription in shared/bus-util.c (as used by systemd-resolved to connect to the system D-Bus instance), calls sdbusset_trusted, which disables access controls for incoming D-Bus messages. An unprivileged user can exploit this by executing D-Bus methods that should be restricted to privileged users, in order to change the system's DNS resolver settings.
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "binary_name": "libnss-myhostname", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-myhostname-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-mymachines", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-mymachines-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-resolve", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-resolve-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-systemd", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libnss-systemd-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libpam-systemd", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libpam-systemd-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libsystemd-dev", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libsystemd0", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libsystemd0-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libudev-dev", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libudev1", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libudev1-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "libudev1-udeb", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-container", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-container-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-coredump", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-coredump-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-journal-remote", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-journal-remote-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-sysv", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-tests", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "systemd-tests-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "udev", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "udev-dbgsym", "binary_version": "237-3ubuntu10.28" }, { "binary_name": "udev-udeb", "binary_version": "237-3ubuntu10.28" } ] }