SSH also supports host based authentication. In contrast to the totally
insecure rsh, the hostnames are checked cryptographically. The
authorization checks are still done with the same syntax as with rsh.
In addition to the old rhosts/rlogin (and eqviv) file, SSH adds the
slogin file. This must not be writable as well, as attackers could
elevate their privileges.
The old rsh (remote shell) grants access to users and hosts in the files
/etc/hosts.equiv and ~/r(login|hosts). If attackers can write to those
files, he can logon as a different user or even root (in case of roots
.r(login|hosts) only) to the system. While the rsh daemon usually checks
for non-root owners or write permissions, this may not be the case on
any system.
Those files might affect other services as well (rlogin, rcp, ...).
As hostnames and usernames are not verified securely, the use of rsh and
similar commands discouraged. It may still be in use on legacy systems
even today, so it should be secured as much as possible if not possible
to remove/replace.
Check also certificates in DER (*.cer, *.der) format. Add
/etc/refind.d/keys to list of certificate paths.
Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
The package maintainers are not immune to mistakes or they might not
always provide timely updates, so let's check (optionally) more
certificates even if they are delivered by packages.
I found three expired certificates in my Debian/unstable system,
thanks to changed Lynis.
Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
from https://lwn.net/Articles/420403/:
"""
The %pK format specifier is designed to hide exposed kernel
pointers, specifically via /proc interfaces. Exposing these
pointers provides an easy target for kernel write vulnerabilities,
since they reveal the locations of writable structures containing
easily triggerable function pointers. The behavior of %pK depends
on the kptr_restrict sysctl. […] If kptr_restrict is set to 2,
kernel pointers using %pK are printed as 0's regardless of
privileges.
"""