bdda640da1
* Make stats file interval configurable
New argument --stats_interval=<msec> controls the interval at which
statistics are written to the stats file. The default is 5000 ms (5 sec)
which matches the prior hardcoded interval.
The stats interval is triggered via signals, so an interval below ~250ms
will probably interfere with falco's behavior.
* Add ability to emit general purpose messages
A new method falco_outputs::handle_msg allows emitting generic messages
that have a "rule", message, and output fields, but aren't exactly tied
to any event and aren't passed through an event formatter.
This allows falco to emit "events" based on internal checks like kernel
buffer overflow detection.
* Clean up newline handling for logging
Log messages from falco_logger::log may or may not have trailing
newlines. Handle both by always adding a newline to stderr logs and
always removing any newline from syslog logs.
* Add method to get sequence from subkey
New variant of get_sequence that allows fetching a list of items from a
key + subkey, for example:
key:
subkey:
- list
- items
- here
Both use a shared method get_sequence_from_node().
* Monitor syscall event drops + optional actions
Start actively monitoring the kernel buffer for syscall event drops,
which are visible in scap_stats.n_drops, and add the ability
to take actions when events are dropped. The -v (verbose) and
-s (stats filename) arguments also print out information on dropped
events, but they were only printed/logged without any actions.
In falco config you can specify one or more of the following actions to
take when falco notes system call drops:
- ignore (do nothing)
- log a critical message
- emit an "internal" falco alert. It looks like any other alert with a
time, "rule", message, and output fields but is not related to any
rule in falco_rules.yaml/other rules files.
- exit falco (the idea being that the restart would be monitored
elsewhere).
A new module syscall_event_drop_mgr is called for every event and
collects scap stats every second. If in the prior second there were
drops, perform_actions() handles the actions.
To prevent potential flooding in high drop rate environments, actions
are goverened by a token bucket with a rate of 1 actions per 30 seconds,
with a max burst of 10 seconds. We might tune this later based on
experience in busy environments.
This might be considered a fix for
https://github.com/falcosecurity/falco/issues/545. It doesn't
specifically flag falco rules alerts when there are drops, but does
make it easier to notice when there are drops.
* Add unit test for syscall event drop detection
Add unit tests for syscall event drop detection. First, add an optional
config option that artifically increments the drop count every
second. (This is only used for testing).
Then add test cases for each of the following:
- No dropped events: should not see any log messages or alerts.
- ignore action: should note the drops but not log messages or alert.
- log action: should only see log messages for the dropped events.
- alert action: should only see alerts for the dropped events.
- exit action: should see log message noting the dropped event and exit
with rc=1
A new trace file ping_sendto.scap has 10 seconds worth of events to
allow the periodic tracking of drops to kick in.
Falco
Latest release
v0.14.0 Read the change log
Dev Branch: 
Master Branch: 
CII Best Practices:
Overview
Falco is a behavioral activity monitor designed to detect anomalous activity in your applications. Powered by sysdig’s system call capture infrastructure, Falco lets you continuously monitor and detect container, application, host, and network activity... all in one place, from one source of data, with one set of rules.
Falco is hosted by the Cloud Native Computing Foundation (CNCF) as a sandbox level project. If you are an organization that wants to help shape the evolution of technologies that are container-packaged, dynamically-scheduled and microservices-oriented, consider joining the CNCF. For details read the Falco CNCF project proposal.
What kind of behaviors can Falco detect?
Falco can detect and alert on any behavior that involves making Linux system calls. Falco alerts can be triggered by the use of specific system calls, their arguments, and by properties of the calling process. For example, you can easily detect things like:
- A shell is run inside a container
- A container is running in privileged mode, or is mounting a sensitive path like
/procfrom the host. - A server process spawns a child process of an unexpected type
- Unexpected read of a sensitive file (like
/etc/shadow) - 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 Falco is “How does it compare to other tools like SELinux, AppArmor, Auditd, etc. that also have security policies?”. We wrote a blog post comparing Falco to other tools.
Documentation
Visit the wiki for full documentation on falco.
Join the Community
- Website for Falco.
- We are working on a blog for the Falco project. In the meantime you can find Falco posts over on the Sysdig blog.
- Join our Public Slack channel for open source sysdig and Falco announcements and discussions.
License Terms
Falco is licensed to you under the Apache 2.0 open source license.
Contributor License Agreements
Background
We are formalizing the way that we accept contributions of code from the contributing community. We must now ask that contributions to falco be provided subject to the terms and conditions of a Contributor License Agreement (CLA). The CLA comes in two forms, applicable to contributions by individuals, or by legal entities such as corporations and their employees. We recognize that entering into a CLA with us involves real consideration on your part, and we’ve tried to make this process as clear and simple as possible.
We’ve modeled our CLA off of industry standards, such as the CLA used by Kubernetes. Note that this agreement is not a transfer of copyright ownership, this simply is a license agreement for contributions, intended to clarify the intellectual property license granted with contributions from any person or entity. It is for your protection as a contributor as well as the protection of falco; it does not change your rights to use your own contributions for any other purpose.
For some background on why contributor license agreements are necessary, you can read FAQs from many other open source projects:
- Django’s excellent CLA FAQ
- A well-written chapter from Karl Fogel’s Producing Open Source Software on CLAs
- The Wikipedia article on CLAs
As always, we are grateful for your past and present contributions to falco.
What do I need to do in order to contribute code?
At first, you need do all changes based on dev branch not master branch.
Individual contributions: Individuals who wish to make contributions must review the Individual Contributor License Agreement and indicate agreement by adding the following line to every GIT commit message:
falco-CLA-1.0-signed-off-by: Joe Smith <joe.smith@email.com>
Use your real name; pseudonyms or anonymous contributions are not allowed.
Corporate contributions: Employees of corporations, members of LLCs or LLPs, or others acting on behalf of a contributing entity, must review the Corporate Contributor License Agreement, must be an authorized representative of the contributing entity, and indicate agreement to it on behalf of the contributing entity by adding the following lines to every GIT commit message:
falco-CLA-1.0-contributing-entity: Full Legal Name of Entity
falco-CLA-1.0-signed-off-by: Joe Smith <joe.smith@email.com>
Use a real name of a natural person who is an authorized representative of the contributing entity; pseudonyms or anonymous contributions are not allowed.
Government contributions: Employees or officers of the United States Government, must review the Government Contributor License Agreement, must be an authorized representative of the contributing entity, and indicate agreement to it on behalf of the contributing entity by adding the following lines to every GIT commit message:
falco-CLA-1.0-contributing-govt-entity: Full Legal Name of Entity
falco-CLA-1.0-signed-off-by: Joe Smith <joe.smith@email.com>
This file is a work of authorship of an employee or officer of the United States Government and is not subject to copyright in the United States under 17 USC 105.
Use a real name of a natural person who is an authorized representative of the contributing entity; pseudonyms or anonymous contributions are not allowed.