Do another round of rule cleanups now that we have a larger set of
positive and negative trace files to work with. Outside of this commit,
there are now trace files for all the positive rules, a docker-compose
startup and teardown, and some trace files from the sysdig cloud staging
environment.
Also add a script that runs sysdig with a filter that removes all the
syscalls not handled by falco as well as a few other high-volume,
low-information syscalls. This script was used to create the staging
environment trace files.
Notable rule changes:
- The direction for write_binary_dir/write_etc needs to be exit instead
of enter, as the bin_dir clause works on the file descriptor returned
by the open/openat call.
- Add login as a trusted binary that can read sensitive files (occurs
for direct console logins).
- sshd can read sensitive files well after startup, so exclude it from
the set of binaries that can trigger
read_sensitive_file_trusted_after_startup.
- limit run_shell_untrusted to non-containers.
- Disable the ssh_error_syslog rule for now. With the current
restriction on system calls (no read/write/sendto/recvfrom/etc), you
won't see the ssh error messages. Nevertheless, add a string to look
for to indicate ssh errors and add systemd's true location for the
syslog device.
- Sshd attemps to setuid even when it's not running as root, so exclude
it from the set of binaries to monitor for now.
- Let programs that are direct decendants of systemd spawn user
management tasks for now.
- Temporarily disable the EACCESS rule. This rule is exposing a bug in
sysdig in debug mode, https://github.com/draios/sysdig/issues/598. The
rule is also pretty noisy so I'll keep it disabled until the sysdig bug
is fixed.
- The etc_dir and bin_dir macros both have the problem that they match
pathnames with /etc/, /bin/, etc in the middle of the path, as sysdig
doesn't have a "begins with" comparison. Add notes for that.
- Change spawn_process to spawned_process to indicate that it's for the
exit side of the execve. Also use it in a few places that were
looking for the same conditions without any macro.
- Get rid of adduser_binaries and fold any programs not already present
into shadowutils_binaries.
- Add new groups sysdigcloud_binaries and sysdigcloud_binaries_parent
and add them as exceptions for write_etc/write_binary_dir.
- Add yum as a package management binary and add it as an exception to
write_etc/write_binary_dir.
- Change how db_program_spawned_process works. Since all of the useful
information is on the exit side of the event, you can't really add a
condition based on the process being new. Isntead, have the rule
check for a non-database-related program being spawned by a
database-related program.
- Allow dragent to run shells.
- Add sendmail, sendmail-msp as a program that attempts to setuid.
- Some of the *_binaries macros that were based on dpkg -L accidentally
contained directories in addition to end files. Trim those.
- Add systemd-logind as a login_binary.
- Add unix_chkpwd as a shadowutils_binary.
- Add parentheses around any macros that group items using or. I found
this necessary when the macro is used in the middle of a list of and
conditions.
- Break out system_binaries into a new subset user_mgmt_binaries
containing login_, passwd_, and shadowutils_ binaries. That way you
don't have to pull in all of system_binaries when looking for
sensisitive files or user management activity.
- Rename fs-bash to fbash, thinking ahead to its more likely name.
Start using the Avocado framework for automated regression
testing. Create a test FalcoTest in falco_test.py which can run on a
collection of trace files. The script test/run_regression_tests.sh is
responsible for pulling zip files containing the positive (falco should
detect) and negative (falco should not detect) trace files, creating a
Avocado multiplex file that defines all the tests (one for each trace
file), running avocado on all the trace files, and showing full logs for
any test that didn't pass.
The old regression script, which simply ran falco, has been removed.
Modify falco's stats output to show the total number of events detected
for use in the tests.
In travis.yml, pull a known stable version of avocado and build it,
including installing any dependencies, as a part of the build process.
