Falco v0.31.1 releases: Behavioral Activity Monitoring With Container Support

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 micro services-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. Thanks to Sysdig’s core decoding and state tracking functionality, 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 /proc from 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 (ls) makes an outbound network connection

How you use it

Falco is deployed as a long-running daemon. You can install it as a Debian/rpm package on a regular host or container host, or you can deploy it as a container.

Falco is configured via a rules file defining the behaviors and events to watch for, and a general configuration file. Rules are expressed in a high-level, human-readable language. We’ve provided a sample rule file ./rules/falco_rules.yaml as a starting point – you can (and will likely want!) to adapt it to your environment.

When developing rules, one helpful feature is Falco’s ability to read trace files saved by sysdig. This allows you to “record” the offending behavior once, and replay it with Falco as many times as needed while tweaking your rules.

Once deployed, Falco uses the Sysdig kernel module and userspace libraries to watch for any events matching one of the conditions defined in the rule file. If a matching event occurs, a notification is written to the configured output(s).

Falco Alerts

When Falco detects suspicious behavior, it sends alerts via one or more of the following channels:

• Writing to standard error
• Writing to a file
• Writing to syslog
• Pipe to a spawned program. A common use of this output type would be to send an email for every Falco notification.

More details on these alerts are described [here](Falco Alerts).

Changelog v0.31.1

Major Changes

• new: add a new drop category n_drops_scratch_map [#1916] – @Andreagit97
• new: allow to specify multiple –cri options [#1893] – @FedeDP

Minor Changes

• refactor(userspace/falco): replace direct getopt_long() cmdline option parsing with third-party cxxopts library. [#1886] – @mstemm
• update: driver version is b7eb0dd [#1923] – @LucaGuerra

Bug Fixes

• fix(userspace/falco): correct plugins init config conversion from YAML to JSON [#1907] – @jasondellaluce
• fix(userspace/engine): for rules at the informational level being loaded at the notice level [#1885] – @mike-stewart
• chore(userspace/falco): fixes truncated -b option description. [#1915] – @andreabonanno
• update(falco): updates usage description for -o, –option [#1903] – @andreabonanno

Rule Changes

• rule(Detect outbound connections to common miner pool ports): fix url in rule output [#1918] – @jsoref
• rule(macro somebody_becoming_themself): renaming macro to somebody_becoming_themselves [#1918] – @jsoref
• rule(list package_mgmt_binaries): npm added [#1866] – @rileydakota
• rule(Launch Package Management Process in Container): support for detecting npm usage [#1866] – @rileydakota
• rule(Polkit Local Privilege Escalation Vulnerability): new rule created to detect CVE-2021-4034 [#1877] – @darryk10
• rule(macro: modify_shell_history): avoid false-positive alerts triggered by modifications to .zsh_history.new and .zsh_history.LOCK files [#1832] – @m4wh6k
• rule(macro: truncate_shell_history): avoid false-positive alerts triggered by modifications to .zsh_history.new and .zsh_history.LOCK files [#1832] – @m4wh6k
• rule(macro sssd_writing_krb): fixed a false-positive alert that was being generated when SSSD updates /etc/krb5.keytab [#1825] – @mac-chaffee
• rule(macro write_etc_common): fixed a false-positive alert that was being generated when SSSD updates /etc/krb5.keytab [#1825] – @mac-chaffee
• upgrade macro(keepalived_writing_conf) [#1742] – @pabloopez
• rule_output(Delete Bucket Public Access Block) typo [#1888] – @pabloopez

Non user-facing changes

• fix(build): fix civetweb linking in cmake module [#1919] – @LucaGuerra
• chore(userspace/engine): remove unused lua functions and state vars [#1908] – @jasondellaluce
• fix(userspace/falco): applies FALCO_INSTALL_CONF_FILE as the default … [#1900] – @andreabonanno
• fix(scripts): correct typo in falco-driver-loader help message [#1899] – @leogr
• update(build)!: replaced various PROBE with DRIVER where necessary. [#1887] – @FedeDP
• Add Fairwinds to the adopters list [#1917] – @sudermanjr
• build(cmake): several cmake changes to speed up/simplify builds for external projects and copying files from source-to-build directories [#1905] – @mstemm

Install & Tutorial

Copyright (C) mstemm