- Add flanneld as a privileged container.
- Add parentheses grouping around many of the "x running y"
containers. I haven't found this strictly necessary with their
current use in rules, but this ensures they will be isolated when
used.
- Allow denyhosts to spawn shells--it runs iptables to add/remove hosts
from its deny list.
This is a rework of a PR made by @juju4 that had a bunch of additions
related to running other security/monitoring products, including aide,
bro, icinga2, nagios, ansible, etc.
This overlapped a lot with changes I had been making to reduce
noisiness, so rather than have @juju4 deal with the conflicts I took the
changes and made a separate commit with the non-conflicting additions.
A summary of the changes:
- Add docker-compose as a docker binary.
- Add showq/critical-stack as setuid binaries.
- Add lxd binaries
- Add some additional package management binaries.
- Add support for host intrustion detection systems like aide.
- Add support for network intrustion detections systems like bro.
- Add support for monitoring systems like nagios, icinga2, npcd.
- Other one-off additions to other lists of mail/etc programs.
A new trace file falco-event-generator.scap contains the result of
running the falco event generator in docker, via:
docker run --security-opt seccomp=unconfined sysdig/falco-event-generator:latest /usr/local/bin/event_generator --once
Make sure this trace file detects the exact set of events we expect for
each rule. This required adding a new verification method
check_detections_by_rule that finds the per-rule counts and compares
them to the expected counts, which are included in the test description
under the key "detect_counts".
This is the first time a trace file for a test is actually in one of the
downloaded zip files. This means it will be tested twice (one for simple
detect-or-not, once for actual counts).
Adding this test showed a problem with Run shell in container
rule--since sysdig/falco-event-generator startswith sysdig/falco, it was
being treated as a trusted container. Modify the macro
trusted_containers to not allow falco-event-generator to be trusted.
Small changes to improve the use of falco_event_generator with falco:
- In event_generator, some actions like exec_ls won't trigger
notifications on their own. So exclude them from -a all.
- For all actions, print details on what the action will do.
- For actions that won't result in a falco notification in containers,
note that in the output.
- The short version of --once wasn't working, fix the getopt.
- Explicitly saying -a all wasn't working, fix.
- Don't rely on an external ruleset in the nodejs docker-compose
demo--the built in rules are sufficient now.
- Add a second possible location for denyhosts
- Add PM2 (http://pm2.keymetrics.io/) as a shell spawner.
- There was a bug in use of ansible_running_python. We actually need
two variants depending on whether ansible is the parent or current
process. parent_ansble_running_python is used for Run shell
untrusted, ansible_running_python is used for other rules.
We had added this image while the changes in
https://github.com/draios/falco/pull/177 made it to everyone. This is in
a release now, so we'll remove it from the rule set.
Within the sysdig code there are several ASSERTS() that can occur for
error paths that aren't truly critical, such as:
17:33:52 DEBUG| [stderr] falco: /home/travis/build/draios/sysdig/userspace/libsinsp/parsers.cpp:1657: static void sinsp_parser::parse_openat_dir(sinsp_evt*, char*, int64_t, std::string*): Assertion `false' failed.
Looking at the code, it's not a truly fatal error, just an inability to
find fd information:
----
if(evt->m_fdinfo == NULL)
{
ASSERT(false);
*sdir = "<UNKNOWN>";
}
----
When running regression tests in travis, we don't want these ASSERTs to
cause falco to exit.
To allow this, in CMakeLists.txt only set DRAIOS_DEBUG_FLAGS if it
wasn't already set, and in travis's cmake, add -DNDEBUG to
DRAIOS_DEBUG_FLAGS.
Several changes to reduce spurious alerts when managing machines via
ansible:
- Add ansible_running_python (that is, ansible-spawned python scripts)
as scripts that can read sensitive files and write below
/etc. Notably this is the user ansible module.
- Also add comments to ansible_running_python suggesting users make it
more strict by specifically naming the root directory for ansible
scripts.
- Add pypy as a python variant that can run ansible-related scripts.
Also other changes to reduce FPs:
- add apt-add-reposit, apt-auto-remova (truncation intentional),
apt-get, apt, apt-key as package management programs, and add package
management binaries to the set of shell spawners. The overlapping
binaries that were in known_shell_spawn_binaries were removed.
- add passwd_binaries, gpg, insserv, apparmor_parser, update-mime,
tzdata.{config,postinst}, systemd-machine, and debconf-show to
the set of binaries that can write below /etc.
- Add vsftpd as a program that can read sensitive files.
- Add additional programs (incl. python support programs like pip,
pycompile) as ones that can spawn shells.
- Allow privileged containers to spawn shells.
- Break out the set of files below /dev that are written to with O_CREAT
into a separate list, and add /dev/random,urandom,console to the list.
- Add python running denyhosts as a program that can write below /etc.
- Also add binaries starting with linux-image- as ones that can spawn
shells. These are perl scripts run as a part of installing
linux-image-N.N packages.
Changes to allow shells spawned by ansible. In general this is actually
pretty difficult--on the remote managed machine, ansible performs
actions simply by running python over ssh without any explicit ansible
helper or command line.
One (weak) hint is that the python scripts being run are usually under a
directory with ansible in the name. So use that as the basis for a macro
ansible_running_python. In turn, that macro is used as a negative
condition for the run shell untrusted rule.
This is a pretty fragile and easily exploited condition, so add a note
to the macro saying so.
Feedback from a falco user:
--
to more findings from last night:
logrotate cronjob (Debian default):
Shell spawned by untrusted binary (user=root shell=sh parent=logrotate cmdline=sh -c invoke-rc.d rsyslog rotate > /dev/null logrotate_script /var/log/syslog)
passwd cronjob (Debian default):
Sensitive file opened for reading by non-trusted program (user=root name=cmp command=cmp -s shadow.bak /etc/shadow file=/etc/shadow)
--
New macro cmp_cp_by_passwd allows cmp/cp to be run by passwd to examine
sensitive files. Add logrotate as a program that can spawn a shell.
Also do some cleanups, moving items to lists and splitting long
single-line conditions into multiple lines.
agent-master went out of sync, probably some rebase/forcepush happened
on dev. Used `git merge -s ours agent-master` here to put all the
commits of agent-master on dev and ignoring anything from agent-master.
So now we can merge from dev to agent-master with fast forward and no
conflicts
Add a test that specifically tests truncated outputs. A rule contains an
output field %fd.cport which has no value for an open event. Ensure that
the rule's output has <NA> for the cport and the remainder of the rule's
output is filled in.
Prefix output strings with * so they are always permissive in the
engine.
In falco outputs, which adds its own prefix, remove any leading * before
adding the custom prefix.
Add cchh/sysdig as a trusted container. We'll probably remove this once
the next agent release occurs that has the fix
https://github.com/draios/falco/pull/177.
Also reformat to avoid long lines.
New tests that test every possible override:
- Overriding a rule with one that doesn't match
- Overriding a macro to one that doesn't match
- Overriding a top level list to a binary that doesn't match
- Overriding an embedded list to one that doesn't match
In each case, the override results in no longer matching an open by the
program "cat".
Allow any list/macro/rule to be overridden by a subsequent file. The
persistent state that lives across invocations of load_rules are the 3
arrays ordered_{list,macro,rule}_names, which have the
lists/macros/rules in the order in which they first appear, and tables
{rules,macros,lists}_by_name, which maps from a name to a yaml object.
With each call to load_rules, the set of loaded rules is reset and the
state of expanded lists, compiled macros, compiled rules, and rule
metadata are recreated from scratch, using the ordered_*_names arrays
and *_by_name tables. That way, any list/macro/rule can be redefined in
a subsequent file with new values.
Add the ability to clear the set of loaded rules from lua. It simply
recreates the sinsp_evttype_filter instance m_evttype_filter, which is
now a unique_ptr.
Periodically both apt and apt-get will spawn shells to update success timestamps and motd.
falco-CLA-1.0-signed-off-by: Jonathan Coetzee <jon@thancoetzee.com>
SSH'ing into an Ubuntu 16.04 box triggers a bunch of "Sensitive file opened for reading by non-trusted program" errors caused by systemd
falco-CLA-1.0-signed-off-by: Jonathan Coetzee jon@thancoetzee.com
sinsp_utils::get_current_time_ns() has the same purpose as
get_epoch_ns(), and now that we're including the token bucket in
falco_engine, it's easy to package the dependency. So use that function
instead.
Add token-bucket based rate limiting for falco notifications.
The token bucket is implemented in token_bucket.cpp (actually in the
engine directory, just to make it easier to include in other
programs). It maintains a current count of tokens (i.e. right to send a
notification). Its main method is claim(), which attemps to claim a
token and returns true if one was claimed successfully. It has a
configurable configurable max burst size and rate. The token bucket
gains "rate" tokens per second, up to a maximum of max_burst tokens.
These parameters are configurable in falco.yaml via the config
options (defaults shown):
outputs:
rate: 1
max_burst: 1000
In falco_outputs::handle_event(), try to claim a token, and if
unsuccessful log a debug message and return immediately.
Add google_containers/kube-proxy as a trusted image (can be run
privileged, can mount sensitive filesystems). While our k8s deployments
run kube-proxy via the hyperkube image, evidently it's sometimes run via
its own image.
This is one of the fixes for #156.
Also update the output message for this rule.
Previously, log messages had levels, but it only influenced the level
argument passed to syslog(). Now, add the ability to control log level
from falco itself.
New falco.yaml argument "log_level" can be one of the strings
corresponding to the well-known syslog levels, which is converted to a
syslog-style level as integer.
In falco_logger::log(), skip messages below the specified level.
Instead of creating a formatter for each event, cache them and create
them only when needed. A new function output_cleanup cleans up the
cached formatters, and is called in the destructor if init() was called.
New argument --metric, which can be cpu|drops, controls whether to graph
cpu usage or event drop percentage. Titles/axis labels/etc. change
appropriately.
When run via scripts like run_performance_tests.sh, it's useful to
include extra info like the test being run and the specific program
variant to the stats file. So support that via the
environment. Environment keys starting with FALCO_STATS_EXTRA_XXX will
have the XXX and environment value added to the stats file.
It's undocumented as I doubt other programs will need this functionality
and it keeps the docs simpler.
With -s, periodically fetch capture stats from the inspector and write
them to the provided file.
Separate class StatsFileWriter handles the details. It does rely on a
timer + SIGALRM handler so you can only practically create a single
object, but it does keep the code/state separate.
The output format has a sample number, the set of current stats, a
delta with the difference from the prior sample, and the percentage of
events dropped during that sample.
Change falco_engine::process_event to return a unique_ptr that wraps the
rule result, so it won't be leaked if this method throws an exception.
This means that callers don't need to create their own.
Add the ability to check falco's return code with exit_status and to
generally match stderr with stderr_contains in a test.
Use those to create a test that has an invalid output expression using
%not_a_real_field. It expects falco to exit with 1 and the output to
contain a message about the invalid output.
Validate rule outputs when loading rules by attempting to create a
formatter based on the rule's output field. If there's an error, it will
propagate up through load_rules and cause falco to exit rather than
discover the problem only when trying to format the event and the rule's
output field.
This required moving formats.{cpp,h} into the falco engine directory
from the falco general directory. Note that these functions are loaded
twice in the two lua states used by falco (engine and outputs).
There's also a couple of minor cleanups:
- falco_formats had a private instance variable that was unused, remove
it.
- rename the package for the falco_formats functions to formats instead
of falco so it's more standalone.
- don't throw a c++ exception in falco_formats::formatter. Instead
generate a lua error, which is handled more cleanly.
- free_formatter doesn't return any values, so set the return value of
the function to 0.
container.info handling used to be handled by the the falco_outputs
object. However, this caused problems for applications that only used
the falco engine, doing their own output formatting for matching events.
Fix this by moving output formatting into the falco engine itself. The
part that replaces %container.info/adds extra formatting to the end of a
rule's output now happens while loading the rule.
Make necessary changes to allow run_performance_tests to invoke the
'test_mm' program we use internally.
Also add ability to run with a build directory separate from the source
directory and to specify an alternate rules file.
Finally, set up the kubernetes demo using sudo, a result of recent changes.
Related to the changes in https://github.com/draios/agent/pull/267,
improve error messages when trying to load sets of rules with errors:
- Check that yaml parsing of rules_content actually resulted in
something.
- Return an error for rules that have an empty name.
- Return an error for yaml objects that aren't a rule/macro/list.
- When compiling, don't print an error message, simply return one,
including a wrapper "can not compile ..." string.
Instead of having FALCO_SHARE_DIR be a relative path, fully specify it
by prepending CMAKE_INSTALL_PREFIX in the top level CMakeLists.txt and
don't prepend CMAKE_INSTALL_PREFIX in config_falco_engine.h.in. This
makes it consistent with its use in the agent.
Honor a USE_BUNDLED_DEPS option for third-party libraries which can be
applied globally. There are also USE_BUNDLED_XXX options that can be
used individually for each library.
Verified that this works by first building with USE_BUNDLED_DEPS=ON (the
default), installing external packages ncurses-dev libssl-dev
libcurl4-openssl-dev so CMake's find_package could use them, modifying
the CMakeLists.txt to add "PATHS ${PROJECT_BINARY_DIR}/..." options to
each find_path()/find_library() command to point to the previously
installed third party libraries. It found them as expected.
The sysdig fix in https://github.com/draios/sysdig/pull/672 forced this
change, but it does also happen to fix a falco feature request
https://github.com/draios/falco/issues/144.
This helps when running on a system which has the module loaded, but getting
access to the module file is hard for some reason. Since I know that the right
version of the module is loaded I just want falco to connect.
I tested this with this run command:
docker run -e SYSDIG_SKIP_LOAD=1 -it -v /dev:/host/dev -v /proc:/host/proc --privileged falco
And it successfully connected to Sysdig and started printing out warnings for my
system.
falco-CLA-1.0-signed-off-by: Carl Sverre accounts@carlsverre.com
SSH'ing into an Ubuntu 16.04 box triggers a bunch of "Sensitive file opened for reading by non-trusted program" errors caused by systemd
falco-CLA-1.0-signed-off-by: Jonathan Coetzee jon@thancoetzee.com
Make sure falco doesn't detect the things draios-agent does as
suspicious. It's possible that you might run open source falco alongside
sysdig cloud.
App checks spawned by sysdig cloud binaries might also change namespace,
so also allow children of sysdigcloud binaries to call setns.
Collect stats on the number of events processed and dropped. When run
with -v, print these stats. This duplicates syddig behavior and can be
useful when dianosing problems related to dropped events throwing off
internal state tracking.
Bring over functionality from sysdig to write trace files. This is easy
as all of the code to actually write the files is in the inspector. This
just handles the -w option and arguments.
This can be useful to write a trace file in parallel with live event
monitoring so you can reproduce it later.
Add a new list k8s_binaries and allow those binaries to do things like
setns/spawn shells. It's not the case that all of these binaries
actually do these things, but keeping it as a single list makes
management easier.
The logic for detecting if a file exists was backwards. It would treat a
file as existing if it could *not* be opened. Reverse that logic so it
works.
This fixes https://github.com/draios/falco/issues/135.
Copy handling of -pk/-pm/-pc/-k/-m arguments from sysdig. All of the
relevant code was already in the inspector so that was easy.
The information from k8s/mesos/containers is used in two ways:
- In rule outputs, if the format string contains %container.info, that
is replaced with the value from -pk/-pm/-pc, if one of those options
was provided. If no option was provided, %container.info is replaced
with a generic %container.name (id=%container.id) instead.
- If the format string does not contain %container.info, and one of
-pk/-pm/-pc was provided, that is added to the end of the formatting
string.
- If -p was specified with a general value (i.e. not
kubernetes/mesos/container), the value is simply added to the end and
any %container.info is replaced with the generic value.
There are a lot of command line options now, so sort them alphabetically
in the usage and getopt handling to make them easier to find.
Also rename -p <pidfile> to -P <pidfile>, thinking ahead to the next
commit.
Add jq to the docker image containing falco. jq is very handy for
transforming json, which comes into play if you want to post to
slack (or other) webhooks.
Add an exfiltration action that reads /etc/shadow and sends the contents
to a arbitrary ip address and port via a udp datagram.
Add the ability to specify actions via the environment instead of the
command line. If actions are specified via the environment, they replace
any actions specified on the command line.
The new privileged falco rule was noisy when running kubernetes, which
can run privileged. Add it to the trusted_containers list.
Also eliminate a couple spurious warnings related to spawning shells in
containers.
New rule 'File Open by Privileged Container' triggers when a container
that is running privileged opens a file.
New rule 'Sensitive Mount by Container' triggers when a container that
has a sensitive mount opens a file. Currently, a sensitive mount is a
mount of /proc.
This depends on https://github.com/draios/sysdig/pull/655.
If a rule has a enabled attribute, and if the value is false, call the
engine's enable_rule() method to disable the rule. Like add_filter,
there's a static method which takes the object as the first argument and
a non-static method that calls the engine.
This fixes#72.
- In the regression tests, make the config file configurable in the
multiplex file via 'conf_file'.
- A new multiplex file item 'outputs' containing a list of <filename>:
<regex> tuples. For each item, the test reads the file and matches
each line against the regex. A match must be found for the test to
pass.
- Add 2 new tests that test file output and program output. They write
to files below /tmp/falco_outputs/ and the contents are checked to
ensure that alerts are written.
The falco engine changes broke the output methods that take
configuration (like the filename for file output, or the program for
program output). Fix that by properly passing the options argument to
each method's output function.
Falco itself spawns a shell when using program notifications, so add
falco to the set of trusted programs. (Also add some other programs like
make, awk, configure, that are run while building).
New variable FALCO_RULES_DEST_FILENAME allows the rules file to be
installed with a different filename. Not set in the falco repo, but in
the agent repo it's installed as falco_rules.default.yaml.
Improve ruleset after using with falco event_generator:
- Instead of assuming all shells are bash, add a list shell_binaries
and macro shell_procs, and replace references to bash with
shell_procs. This revealed some other programs that can spawn shells.
- Add "login" as an interactive command. systemd-login isn't in alpine
linux, which is the linux distro used for the container.
- Move read_sensitive_file_untrusted before
read_sensitive_file_trusted_after_startup, so it can hit first.
C++ program that performs bad activities related to the current falco
ruleset. There are configurable actions for almost all of the current
ruleset, via the --action argument.
By default runs in a loop forever. Can be overridden via --once.
Also add a Dockerfile that compiles event_generator.cpp within an alpine
linux image and copies it to /usr/local/bin. This image has been pushed
to docker hub as "sysdig/falco-event-generator:latest".
Add a Makefile that runs the right docker build command.
Docker 1.12 split docker into docker and dockerd, so add dockerd as a
docker binary. Also be consistent about using docker_binares instead of
just references to docker.
Also add ldconfig as a program that can write to files below /etc.
Add test that cover reading from multiple sets of rule files and
disabling rules. Specific changes:
- Modify falco to allow multiple -r arguments to read from multiple
files.
- In the test multiplex file, add a disabled_rules attribute,
containing a sequence of rules to disable. Result in -D arguments
when running falco.
- In the test multiplex file, 'rules_file' can be a sequence. It
results in multiple -r arguments when running falco.
- In the test multiplex file, 'detect_level' can be a squence of
multiple severity levels. All levels will be checked for in the
output.
- Move all test rules files to a rules subdirectory and all trace files
to a traces subdirectory.
- Add a small trace file for a simple cat of /dev/null. Used by the
new tests.
- Add the following new tests:
- Reading from multiple files, with the first file being
empty. Ensure that the rules from the second file are properly
loaded.
- Reading from multiple files with the last being empty. Ensures
that the empty file doesn't overwrite anything from the first
file.
- Reading from multiple files with varying severity levels for each
rule. Ensures that both files are properly read.
- Disabling rules from a rules file, both with full rule names
and regexes. Will result in not detecting anything.
Add the ability to drop events at the falco engine level in a way that
can scale with the dropping that already occurs at the kernel/inspector
level.
New inline function should_drop_evt() controls whether or not events are
matched against the set of rules, and is controlled by two
values--sampling ratio and sampling multiplier.
Here's how the sampling ratio and multiplier influence whether or not an
event is dropped in should_drop_evt(). The intent is that
m_sampling_ratio is generally changing external to the engine e.g. in
the main inspector class based on how busy the inspector is. A sampling
ratio implies no dropping. Values > 1 imply increasing levels of
dropping. External to the engine, the sampling ratio results in events
being dropped at the kernel/inspector interface. The sampling
multiplier is an amplification to the sampling factor in
m_sampling_ratio. If 0, no additional events are dropped other than
those that might be dropped by the kernel/inspector interface. If 1,
events that make it past the kernel module are subject to an additional
level of dropping at the falco engine, scaling with the sampling ratio
in m_sampling_ratio.
Unlike the dropping that occurs at the kernel level, where the events in
the first part of each second are dropped, this dropping is random.
Move the c++ and lua code implementing falco engine/falco common to its
own directory userspace/engine. It's compiled as a static library
libfalco_engine.a, and has its own CMakeLists.txt so it can be included
by other projects.
The engine's CMakeLists.txt has a add_subdirectory for the falco rules
directory, so including the engine also builds the rules.
The variables you need to set to use the engine's CMakeLists.txt are:
- CMAKE_INSTALL_PREFIX: the root directory below which everything is
installed.
- FALCO_ETC_DIR: where to install the rules file.
- FALCO_SHARE_DIR: where to install lua code, relative to the
- install/package root.
- LUAJIT_INCLUDE: where to find header files for lua.
- FALCO_SINSP_LIBRARY: the library containing sinsp code. It will be
- considered a dependency of the engine.
- LPEG_LIB/LYAML_LIB/LIBYAML_LIB: locations for third-party libraries.
- FALCO_COMPONENT: if set, will be included as a part of any install()
commands.
Instead of specifying /usr/share/falco in config_falco_*.h.in, use
CMAKE_INSTALL_PREFIX and FALCO_SHARE_DIR.
The lua code for the engine has also moved, so the two lua source
directories (userspace/engine/lua and userspace/falco/lua) need to be
available separately via falco_common, so make it an argument to
falco_common::init.
As a part of making it easy to include in another project, also clean up
LPEG build/defs. Modify build-lpeg to add a PREFIX argument to allow for
object files/libraries being in an alternate location, and when building
lpeg, put object files in a build/ subdirectory.
Create standalone classes falco_engine/falco_outputs that can be
embedded in other programs. falco_engine is responsible for matching
events against rules, and falco_output is responsible for formatting an
alert string given an event and writing the alert string to all
configured outputs.
falco_engine's main interfaces are:
- load_rules/load_rules_file: Given a path to a rules file or a string
containing a set of rules, load the rules. Also loads needed lua code.
- process_event(): check the event against the set of rules and return
the results of a match, if any.
- describe_rule(): print details on a specific rule or all rules.
- print_stats(): print stats on the rules that matched.
- enable_rule(): enable/disable any rules matching a pattern. New falco
command line option -D allows you to disable one or more rules on the
command line.
falco_output's main interfaces are:
- init(): load needed lua code.
- add_output(): add an output channel for alert notifications.
- handle_event(): given an event that matches one or more rules, format
an alert message and send it to any output channels.
Each of falco_engine/falco_output maintains a separate lua state and
loads separate sets of lua files. The code to create and initialize the
lua state is in a base class falco_common.
falco_engine no longer logs anything. In the case of errors, it throws
exceptions. falco_logger is now only used as a logging mechanism for
falco itself and as an output method for alert messages. (This should
really probably be split, but it's ok for now).
falco_engine contains an sinsp_evttype_filter object containing the set
of eventtype filters. Instead of calling
m_inspector->add_evttype_filter() to add a filter created by the
compiler, call falco_engine::add_evttype_filter() instead. This means
that the inspector runs with a NULL filter and all events are returned
from do_inspect. This depends on
https://github.com/draios/sysdig/pull/633 which has a wrapper around a
set of eventtype filters.
Some additional changes along with creating these classes:
- Some cleanups of unnecessary header files, cmake include_directory()s,
etc to only include necessary includes and only include them in header
files when required.
- Try to avoid 'using namespace std' in header files, or assuming
someone else has done that. Generally add 'using namespace std' to all
source files.
- Instead of using sinsp_exception for all errors, define a
falco_engine_exception class for exceptions coming from the falco
engine and use it instead. For falco program code, switch to general
exceptions under std::exception and catch + display an error for all
exceptions, not just sinsp_exceptions.
- Remove fields.{cpp,h}. This was dead code.
- Start tracking counts of rules by priority string (i.e. what's in the
falco rules file) as compared to priority level (i.e. roughtly
corresponding to a syslog level). This keeps the rule processing and
rule output halves separate. This led to some test changes. The regex
used in the test is now case insensitive to be a bit more flexible.
- Now that https://github.com/draios/sysdig/pull/632 is merged, we can
delete the rules object (and its lua_parser) safely.
- Move loading the initial lua script to the constructor. Otherwise,
calling load_rules() twice re-loads the lua script and throws away any
state like the mapping from rule index to rule.
- Allow an empty rules file.
Finally, fix most memory leaks found by valgrind:
- falco_configuration wasn't deleting the allocated m_config yaml
config.
- several ifstreams were being created simply to test which falco
config file to use.
- In the lua output methods, an event formatter was being created using
falco.formatter() but there was no corresponding free_formatter().
This depends on changes in https://github.com/draios/sysdig/pull/640.
This file documents all notable changes to Falco. The release numbering uses [semantic versioning](http://semver.org).
## v0.5.0
Released 2016-12-22
Starting with this release, we're adding a new section "Rule Changes" devoted to changes to the default ruleset `falco_rules.yaml`.
### Major Changes
* Cache event formatting objects so they are not re-created for every falco notification. This can result in significant speedups when the ruleset results in lots of notifications. [[#158](https://github.com/draios/falco/pull/158)]
* Falco notifications are now throttled by a token bucket, preventing a flood of notifications when many events match a rule. Controlled by the `outputs, rate` and `outputs, max_burst` options. [[#161](https://github.com/draios/falco/pull/161)]
### Minor Changes
* When run from a container, you can provide the environment variable `SYSDIG_SKIP_LOAD` to skip the process of building/loading the kernel module. Thanks @carlsverre for the fix. [[#145](https://github.com/draios/falco/pull/145)]
* Fully implement `USE_BUNDLED_DEPS` within CMakeFiles so you can build with external third-party libraries. [[#147](https://github.com/draios/falco/pull/147)]
* Improve error messages that result when trying to load a rule with a malformed `output:` attribute [[#150](https://github.com/draios/falco/pull/150)] [[#151](https://github.com/draios/falco/pull/151)]
* Add the ability to write event capture statistics to a file via the `-s <statsfile>` option. [[#155](https://github.com/draios/falco/pull/155)]
* New configuration option `log_level` controls the verbosity of falco's logging. [[#160](https://github.com/draios/falco/pull/160)]
### Bug Fixes
* Improve compatibility with Sysdig Cloud Agent build [[#148](https://github.com/draios/falco/pull/148)]
### Rule Changes
* Add DNF as non-alerting for RPM and package management. Thanks @djcross for the fix. [[#153](https://github.com/draios/falco/pull/153)]
* Make `google_containers/kube-proxy` a trusted image, affecting the File Open by Privileged Container/Sensitive Mount by Container rules. [[#159](https://github.com/draios/falco/pull/159)]
* Add fail2ban-server as a program that can spawn shells. Thanks @jcoetzee for the fix. [[#168](https://github.com/draios/falco/pull/168)]
* Add systemd as a program that can access sensitive files. Thanks @jcoetzee for the fix. [[#169](https://github.com/draios/falco/pull/169)]
* Add apt/apt-get as programs that can spawn shells. Thanks @jcoetzee for the fix. [[#170](https://github.com/draios/falco/pull/170)]
Read the [change log](https://github.com/draios/falco/blob/dev/CHANGELOG.md)
Dev Branch: [](https://travis-ci.org/draios/falco)<br />
@@ -22,6 +22,11 @@ Falco can detect and alert on any behavior that involves making Linux system cal
- A non-device file is written to `/dev`
- A standard system binary (like `ls`) makes an outbound network connection
#### How Falco Compares to Other Security Tools like SELinux, Auditd, etc.
One of the questions we often get when we talk about Sysdig Falco is “How does it compare to other tools like SELinux, AppArmor, Auditd, etc. that also have security policies?”. We wrote a [blog post](https://sysdig.com/blog/selinux-seccomp-falco-technical-discussion/) comparing Falco to other tools.
Documentation
---
[Visit the wiki] (https://github.com/draios/falco/wiki) for full documentation on falco.
and not fd.directory in (/etc/cassandra, /etc/ssl/certs/java)
and not ansible_running_python
and not python_running_denyhosts
- rule:Write below etc
desc:an attempt to write to any file below /etc, not in a pipe installer session
@@ -221,22 +274,33 @@
output:"File below /etc opened for writing (user=%user.name command=%proc.cmdline file=%fd.name) within pipe installer session"
priority:INFO
- macro:cmp_cp_by_passwd
condition:proc.name in (cmp, cp) and proc.pname=passwd
- rule:Read sensitive file trusted after startup
desc:an attempt to read any sensitive file (e.g. files containing user/password/authentication information) by a trusted program after startup. Trusted programs might read these files at startup to load initial state, but not afterwards.
condition:sensitive_files and open_read and server_procs and not proc_is_new and proc.name!="sshd"
output:"Sensitive file opened for reading by trusted program after startup (user=%user.name command=%proc.cmdline file=%fd.name)"
desc:an attempt to read any sensitive file (e.g. files containing user/password/authentication information). Exceptions are made for known trusted programs.
condition:sensitive_files and open_read and not proc.name in (user_mgmt_binaries, userexec_binaries, package_mgmt_binaries, cron_binaries, iptables, ps, lsb_release, check-new-relea, dumpe2fs, accounts-daemon, shell_binaries, sshd) and not proc.cmdline contains /usr/bin/mandb
condition:>
sensitive_files and open_read
and not proc.name in (user_mgmt_binaries, userexec_binaries, package_mgmt_binaries, cron_binaries, read_sensitive_file_binaries, shell_binaries, hids_binaries)
and not cmp_cp_by_passwd
and not ansible_running_python
and not proc.cmdline contains /usr/bin/mandb
output:"Sensitive file opened for reading by non-trusted program (user=%user.name name=%proc.name command=%proc.cmdline file=%fd.name)"
priority:WARNING
# Only let rpm-related programs write to the rpm database
- rule:Write below rpm database
desc:an attempt to write to the rpm database by any non-rpm related program
condition:fd.name startswith /var/lib/rpm and open_write and not proc.name in (dnf,rpm,rpmkey,yum)
condition:fd.name startswith /var/lib/rpm and open_write and not proc.name in (dnf,rpm,rpmkey,yum) and not ansible_running_python
output:"Rpm database opened for writing by a non-rpm program (command=%proc.cmdline file=%fd.name)"
priority:WARNING
@@ -276,18 +340,48 @@
- rule:Change thread namespace
desc:an attempt to change a program/thread\'s namespace (commonly done as a part of creating a container) by calling setns.
condition:evt.type = setns and not proc.name in (docker_binaries, k8s_binaries, sysdigcloud_binaries, sysdig, nsenter) and not proc.pname in (sysdigcloud_binaries)
condition:>
evt.type = setns
and not proc.name in (docker_binaries, k8s_binaries, lxd_binaries, sysdigcloud_binaries, sysdig, nsenter)
and not proc.pname in (sysdigcloud_binaries)
output:"Namespace change (setns) by unexpected program (user=%user.name command=%proc.cmdline parent=%proc.pname %container.info)"
priority:WARNING
- list:known_shell_spawn_binaries
items:[
sshd, sudo, su, tmux, screen, emacs, systemd, login, flock, fbash,
desc:an attempt to spawn a shell by a non-shell program. Exceptions are made for trusted binaries.
condition:spawned_process and not container and shell_procs and proc.pname exists and not proc.pname in (cron_binaries, shell_binaries, sshd, sudo, docker_binaries, k8s_binaries, su, tmux, screen, emacs, systemd, login, flock, fbash, nginx, monit, supervisord, dragent, aws, initdb, docker-compose, make, configure, awk, falco)
output:"Shell spawned by untrusted binary (user=%user.name shell=%proc.name parent=%proc.pname cmdline=%proc.cmdline)"
condition:>
spawned_process and not container
and shell_procs
and proc.pname exists
and not proc.pname in (cron_binaries, shell_binaries, known_shell_spawn_binaries, docker_binaries,
output:"Shell spawned by untrusted binary (user=%user.name shell=%proc.name parent=%proc.pname cmdline=%proc.cmdline pcmdline=%proc.pcmdline)"
priority:WARNING
- macro:trusted_containers
condition:(container.image startswith sysdig/agent or container.image startswith sysdig/falco or container.image startswith sysdig/sysdig or container.image startswith gcr.io/google_containers/hyperkube or container.image startswith gcr.io/google_containers/kube-proxy)
condition:(container.image startswith sysdig/agent or
(container.image startswith sysdig/falco and
not container.image startswith sysdig/falco-event-generator) or
container.image startswith sysdig/sysdig or
container.image startswith gcr.io/google_containers/hyperkube or
container.image startswith quay.io/coreos/flannel or
desc:Any open by a privileged container. Exceptions are made for known trusted images.
@@ -317,7 +411,13 @@
- rule:Run shell in container
desc:a shell was spawned by a non-shell program in a container. Container entrypoints are excluded.
condition:spawned_process and container and shell_procs and proc.pname exists and not proc.pname in (shell_binaries, docker_binaries, k8s_binaries, initdb, pg_ctl, awk, apache2, falco, cron)
condition:>
spawned_process and container
and shell_procs
and proc.pname exists
and not proc.pname in (shell_binaries, docker_binaries, k8s_binaries, lxd_binaries, aide_wrapper_binaries, nids_binaries,
output:"Shell spawned in a container other than entrypoint (user=%user.name %container.info shell=%proc.name parent=%proc.pname cmdline=%proc.cmdline)"
priority:WARNING
@@ -340,8 +440,8 @@
# sshd, mail programs attempt to setuid to root even when running as non-root. Excluding here to avoid meaningless FPs
- rule:Non sudo setuid
desc:an attempt to change users by calling setuid. sudo/su are excluded. user "root" is also excluded, as setuid calls typically involve dropping privileges.
condition:evt.type=setuid and evt.dir=> and not user.name=root and not proc.name in (userexec_binaries, mail_binaries, sshd, dbus-daemon-lau)
output:"Unexpected setuid call by non-sudo, non-root program (user=%user.name command=%proc.cmdline uid=%evt.arg.uid)"
condition:evt.type=setuid and evt.dir=> and not user.name=root and not proc.name in (userexec_binaries, mail_binaries, sshd, dbus-daemon-lau, ping, ping6, critical-stack-)
output:"Unexpected setuid call by non-sudo, non-root program (user=%user.name parent=%proc.pname command=%proc.cmdline uid=%evt.arg.uid)"
priority:WARNING
- rule:User mgmt binaries
@@ -350,10 +450,17 @@
output:"User management binary command run outside of container (user=%user.name command=%proc.cmdline parent=%proc.pname)"
# (we may need to add additional checks against false positives, see: https://bugs.launchpad.net/ubuntu/+source/rkhunter/+bug/86153)
- rule:Create files below dev
desc:creating any files below /dev other than known programs that manage devices. Some rootkits hide files in /dev.
condition:fd.directory = /dev and (evt.type = creat or (evt.type = open and evt.arg.flags contains O_CREAT)) and proc.name != blkid and not fd.name in (/dev/null,/dev/stdin,/dev/stdout,/dev/stderr,/dev/tty)
condition:>
fd.directory = /dev and
(evt.type = creat or (evt.type = open and evt.arg.flags contains O_CREAT))
and not proc.name in (dev_creation_binaries)
and not fd.name in (allowed_dev_files)
output:"File created below /dev by untrusted program (user=%user.name command=%proc.cmdline file=%fd.name)"
stderr_contains:"Runtime error: Error loading rules:.* Invalid output format 'An open was seen %not_a_real_field': 'invalid formatting token not_a_real_field'. Exiting."
@@ -126,6 +154,14 @@ trace_files: !mux
- rules/single_rule_enabled_flag.yaml
trace_file:trace_files/cat_write.scap
null_output_field:
detect:True
detect_level:WARNING
rules_file:
- rules/null_output_field.yaml
trace_file:trace_files/cat_write.scap
stdout_contains:"Warning An open was seen .cport=<NA> command=cat /dev/null."
file_output:
detect:True
detect_level:WARNING
@@ -145,3 +181,22 @@ trace_files: !mux
trace_file:trace_files/cat_write.scap
outputs:
- /tmp/falco_outputs/program_output.txt:Warning An open was seen
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