Introduction
Here are the fields supported by Falco. These fields can be used in the condition key of a Falco rule and well as the output key. Any fields included in the output key of a rule will also be included in the alert’s output_fields object when json_output is set to true.
You can also see this set of fields via falco --list=<source>, with <source> being one of the sources below.
System Calls (source syscall)
syscall event source fields are provided by the kernel module. These fields are identical to the Sysdig filter fields that can be used to filter Sysdig captures.
# System Kernel Fields
$ falco --list=syscall
fd Field Class
Fields for File Descriptors. Includes networking as well as file/directory fields.
fd.num the unique number identifying the file descriptor.
fd.type type of FD. Can be 'file', 'directory', 'ipv4', 'ipv6', 'unix',
'pipe', 'event', 'signalfd', 'eventpoll', 'inotify' or 'signal
fd'.
fd.typechar type of FD as a single character. Can be 'f' for file, 4 for IP
v4 socket, 6 for IPv6 socket, 'u' for unix socket, p for pipe,
'e' for eventfd, 's' for signalfd, 'l' for eventpoll, 'i' for i
notify, 'o' for unknown.
fd.name FD full name. If the fd is a file, this field contains the full
path. If the FD is a socket, this field contain the connection
tuple.
fd.directory If the fd is a file, the directory that contains it.
fd.filename If the fd is a file, the filename without the path.
fd.ip (FILTER ONLY) matches the ip address (client or server) of the
fd.
fd.cip client IP address.
fd.sip server IP address.
fd.lip local IP address.
fd.rip remote IP address.
fd.port (FILTER ONLY) matches the port (either client or server) of the
fd.
fd.cport for TCP/UDP FDs, the client port.
fd.sport for TCP/UDP FDs, server port.
fd.lport for TCP/UDP FDs, the local port.
fd.rport for TCP/UDP FDs, the remote port.
fd.l4proto the IP protocol of a socket. Can be 'tcp', 'udp', 'icmp' or 'ra
w'.
fd.sockfamily the socket family for socket events. Can be 'ip' or 'unix'.
fd.is_server 'true' if the process owning this FD is the server endpoint in
the connection.
fd.uid a unique identifier for the FD, created by chaining the FD numb
er and the thread ID.
fd.containername
chaining of the container ID and the FD name. Useful when tryin
g to identify which container an FD belongs to.
fd.containerdirectory
chaining of the container ID and the directory name. Useful whe
n trying to identify which container a directory belongs to.
fd.proto (FILTER ONLY) matches the protocol (either client or server) of
the fd.
fd.cproto for TCP/UDP FDs, the client protocol.
fd.sproto for TCP/UDP FDs, server protocol.
fd.lproto for TCP/UDP FDs, the local protocol.
fd.rproto for TCP/UDP FDs, the remote protocol.
fd.net (FILTER ONLY) matches the IP network (client or server) of the
fd.
fd.cnet (FILTER ONLY) matches the client IP network of the fd.
fd.snet (FILTER ONLY) matches the server IP network of the fd.
fd.lnet (FILTER ONLY) matches the local IP network of the fd.
fd.rnet (FILTER ONLY) matches the remote IP network of the fd.
fd.connected for TCP/UDP FDs, 'true' if the socket is connected.
fd.name_changed True when an event changes the name of an fd used by this event
. This can occur in some cases such as udp connections where th
e connection tuple changes.
fd.cip.name Domain name associated with the client IP address.
fd.sip.name Domain name associated with the server IP address.
fd.lip.name Domain name associated with the local IP address.
fd.rip.name Domain name associated with the remote IP address.
fd.dev device number (major/minor) containing the referenced file
fd.dev.major major device number containing the referenced file
fd.dev.minor minor device number containing the referenced file
proc & thread Field Class
Fields for running or spawned processes or threads.
Field Class: process
proc.pid the id of the process generating the event.
proc.exe the first command line argument (usually the executable name or
a custom one).
proc.name the name (excluding the path) of the executable generating the
event.
proc.args the arguments passed on the command line when starting the proc
ess generating the event.
proc.env the environment variables of the process generating the event.
proc.cmdline full process command line, i.e. proc.name + proc.args.
proc.exeline full process command line, with exe as first argument, i.e. pro
c.exe + proc.args.
proc.cwd the current working directory of the event.
proc.nthreads the number of threads that the process generating the event cur
rently has, including the main process thread.
proc.nchilds the number of child threads that the process generating the eve
nt currently has. This excludes the main process thread.
proc.ppid the pid of the parent of the process generating the event.
proc.pname the name (excluding the path) of the parent of the process gene
rating the event.
proc.pcmdline the full command line (proc.name + proc.args) of the parent of
the process generating the event.
proc.apid the pid of one of the process ancestors. E.g. proc.apid[1] retu
rns the parent pid, proc.apid[2] returns the grandparent pid, a
nd so on. proc.apid[0] is the pid of the current process. proc.
apid without arguments can be used in filters only and matches
any of the process ancestors, e.g. proc.apid=1234.
proc.aname the name (excluding the path) of one of the process ancestors.
E.g. proc.aname[1] returns the parent name, proc.aname[2] retur
ns the grandparent name, and so on. proc.aname[0] is the name o
f the current process. proc.aname without arguments can be used
in filters only and matches any of the process ancestors, e.g.
proc.aname=bash.
proc.loginshellid
the pid of the oldest shell among the ancestors of the current
process, if there is one. This field can be used to separate di
fferent user sessions, and is useful in conjunction with chisel
s like spy_user.
proc.duration number of nanoseconds since the process started.
proc.fdopencount
number of open FDs for the process
proc.fdlimit maximum number of FDs the process can open.
proc.fdusage the ratio between open FDs and maximum available FDs for the pr
ocess.
proc.vmsize total virtual memory for the process (as kb).
proc.vmrss resident non-swapped memory for the process (as kb).
proc.vmswap swapped memory for the process (as kb).
thread.pfmajor number of major page faults since thread start.
thread.pfminor number of minor page faults since thread start.
thread.tid the id of the thread generating the event.
thread.ismain 'true' if the thread generating the event is the main one in th
e process.
thread.exectime CPU time spent by the last scheduled thread, in nanoseconds. Ex
ported by switch events only.
thread.totexectime
Total CPU time, in nanoseconds since the beginning of the captu
re, for the current thread. Exported by switch events only.
thread.cgroups all the cgroups the thread belongs to, aggregated into a single
string.
thread.cgroup the cgroup the thread belongs to, for a specific subsystem. E.g
. thread.cgroup.cpuacct.
thread.vtid the id of the thread generating the event as seen from its curr
ent PID namespace.
proc.vpid the id of the process generating the event as seen from its cur
rent PID namespace.
thread.cpu the CPU consumed by the thread in the last second.
thread.cpu.user the user CPU consumed by the thread in the last second.
thread.cpu.system
the system CPU consumed by the thread in the last second.
thread.vmsize For the process main thread, this is the total virtual memory f
or the process (as kb). For the other threads, this field is ze
ro.
thread.vmrss For the process main thread, this is the resident non-swapped m
emory for the process (as kb). For the other threads, this fiel
d is zero.
proc.sid the session id of the process generating the event.
proc.sname the name of the current process's session leader. This is eithe
r the process with pid=proc.sid or the eldest ancestor that has
the same sid as the current process.
proc.tty The controlling terminal of the process. 0 for processes withou
t a terminal.
proc.exepath The full executable path of the process.
proc.vpgid the process group id of the process generating the event, as se
en from its current PID namespace.
proc.is_container_healthcheck
true if this process is running as a part of the container's he
alth check.
evt Field Class
Fields for system call events. Use evt.type to specify the system call name. At least one evt field is required per Falco syscall rule.
evt.num event number.
evt.time event timestamp as a time string that includes the nanosecond p
art.
evt.time.s event timestamp as a time string with no nanoseconds.
evt.time.iso8601
event timestamp in ISO 8601 format, including nanoseconds and t
ime zone offset (in UTC).
evt.datetime event timestamp as a time string that includes the date.
evt.rawtime absolute event timestamp, i.e. nanoseconds from epoch.
evt.rawtime.s integer part of the event timestamp (e.g. seconds since epoch).
evt.rawtime.ns fractional part of the absolute event timestamp.
evt.reltime number of nanoseconds from the beginning of the capture.
evt.reltime.s number of seconds from the beginning of the capture.
evt.reltime.ns fractional part (in ns) of the time from the beginning of the c
apture.
evt.latency delta between an exit event and the correspondent enter event,
in nanoseconds.
evt.latency.s integer part of the event latency delta.
evt.latency.ns fractional part of the event latency delta.
evt.latency.human
delta between an exit event and the correspondent enter event,
as a human readable string (e.g. 10.3ms).
evt.deltatime delta between this event and the previous event, in nanoseconds
.
evt.deltatime.s integer part of the delta between this event and the previous e
vent.
evt.deltatime.ns
fractional part of the delta between this event and the previou
s event.
evt.outputtime this depends on -t param, default is %evt.time ('h').
evt.dir event direction can be either '>' for enter events or '<' for e
xit events.
evt.type The name of the event (e.g. 'open').
evt.type.is allows one to specify an event type, and returns 1 for events t
hat are of that type. For example, evt.type.is.open returns 1 f
or open events, 0 for any other event.
syscall.type For system call events, the name of the system call (e.g. 'open
'). Unset for other events (e.g. switch or Sysdig internal even
ts). Use this field instead of evt.type if you need to make sur
e that the filtered/printed value is actually a system call.
evt.category The event category. Example values are 'file' (for file operati
ons like open and close), 'net' (for network operations like so
cket and bind), memory (for things like brk or mmap), and so on
.
evt.cpu number of the CPU where this event happened.
evt.args all the event arguments, aggregated into a single string.
evt.arg one of the event arguments specified by name or by number. Some
events (e.g. return codes or FDs) will be converted into a tex
t representation when possible. E.g. 'evt.arg.fd' or 'evt.arg[0
]'.
evt.rawarg one of the event arguments specified by name. E.g. 'evt.rawarg.
fd'.
evt.info for most events, this field returns the same value as evt.args.
However, for some events (like writes to /dev/log) it provides
higher level information coming from decoding the arguments.
evt.buffer the binary data buffer for events that have one, like read(), r
ecvfrom(), etc. Use this field in filters with 'contains' to se
arch into I/O data buffers.
evt.buflen the length of the binary data buffer for events that have one,
like read(), recvfrom(), etc.
evt.res event return value, as a string. If the event failed, the resul
t is an error code string (e.g. 'ENOENT'), otherwise the result
is the string 'SUCCESS'.
evt.rawres event return value, as a number (e.g. -2). Useful for range com
parisons.
evt.failed 'true' for events that returned an error status.
evt.is_io 'true' for events that read or write to FDs, like read(), send,
recvfrom(), etc.
evt.is_io_read 'true' for events that read from FDs, like read(), recv(), recv
from(), etc.
evt.is_io_write 'true' for events that write to FDs, like write(), send(), etc.
evt.io_dir 'r' for events that read from FDs, like read(); 'w' for events
that write to FDs, like write().
evt.is_wait 'true' for events that make the thread wait, e.g. sleep(), sele
ct(), poll().
evt.wait_latency
for events that make the thread wait (e.g. sleep(), select(), p
oll()), this is the time spent waiting for the event to return,
in nanoseconds.
evt.is_syslog 'true' for events that are writes to /dev/log.
evt.count This filter field always returns 1 and can be used to count eve
nts from inside chisels.
evt.count.error This filter field returns 1 for events that returned with an er
ror, and can be used to count event failures from inside chisel
s.
evt.count.error.file
This filter field returns 1 for events that returned with an er
ror and are related to file I/O, and can be used to count event
failures from inside chisels.
evt.count.error.net
This filter field returns 1 for events that returned with an er
ror and are related to network I/O, and can be used to count ev
ent failures from inside chisels.
evt.count.error.memory
This filter field returns 1 for events that returned with an er
ror and are related to memory allocation, and can be used to co
unt event failures from inside chisels.
evt.count.error.other
This filter field returns 1 for events that returned with an er
ror and are related to none of the previous categories, and can
be used to count event failures from inside chisels.
evt.count.exit This filter field returns 1 for exit events, and can be used to
count single events from inside chisels.
evt.around (FILTER ONLY) Accepts the event if it's around the specified ti
me interval. The syntax is evt.around[T]=D, where T is the valu
e returned by %evt.rawtime for the event and D is a delta in mi
lliseconds. For example, evt.around[1404996934793590564]=1000 w
ill return the events with timestamp with one second before the
timestamp and one second after it, for a total of two seconds
of capture.
evt.abspath Absolute path calculated from dirfd and name during syscalls li
ke renameat and symlinkat. Use 'evt.abspath.src' or 'evt.abspat
h.dst' for syscalls that support multiple paths.
evt.is_open_read
'true' for open/openat events where the path was opened for rea
ding
evt.is_open_write
'true' for open/openat events where the path was opened for wri
ting
user Field Class
Fields related to the user executing the event.
user.uid user ID.
user.name user name.
user.homedir home directory of the user.
user.shell user's shell.
user.loginuid audit user id (auid).
user.loginname audit user name (auid).
group Field Class
Fields related to the group of the user executing the event.
group.gid group ID.
group.name group name.
syslog Field Class
Fields related to messages sent to syslog. Allows rules to be created based on syslog messages.
syslog.facility.str
facility as a string.
syslog.facility facility as a number (0-23).
syslog.severity.str
severity as a string. Can have one of these values: emerg, aler
t, crit, err, warn, notice, info, debug
syslog.severity severity as a number (0-7).
syslog.message message sent to syslog.
container Field Class
Fields related to containers. Allows for filtering based on container.name, container.image, etc.
container.id the container id.
container.name the container name.
container.image the container image name (e.g. sysdig/sysdig:latest for docker,
).
container.image.id
the container image id (e.g. 6f7e2741b66b).
container.type the container type, eg: docker or rkt
container.privileged
true for containers running as privileged, false otherwise
container.mounts
A space-separated list of mount information. Each item in the l
ist has the format <source>:<dest>:<mode>:<rdrw>:<propagation>
container.mount Information about a single mount, specified by number (e.g. con
tainer.mount[0]) or mount source (container.mount[/usr/local]).
The pathname can be a glob (container.mount[/usr/local/*]), in
which case the first matching mount will be returned. The info
rmation has the format <source>:<dest>:<mode>:<rdrw>:<propagati
on>. If there is no mount with the specified index or matching
the provided source, returns the string "none" instead of a NUL
L value.
container.mount.source
the mount source, specified by number (e.g. container.mount.sou
rce[0]) or mount destination (container.mount.source[/host/lib/
modules]). The pathname can be a glob.
container.mount.dest
the mount destination, specified by number (e.g. container.moun
t.dest[0]) or mount source (container.mount.dest[/lib/modules])
. The pathname can be a glob.
container.mount.mode
the mount mode, specified by number (e.g. container.mount.mode[
0]) or mount source (container.mount.mode[/usr/local]). The pat
hname can be a glob.
container.mount.rdwr
the mount rdwr value, specified by number (e.g. container.mount
.rdwr[0]) or mount source (container.mount.rdwr[/usr/local]). T
he pathname can be a glob.
container.mount.propagation
the mount propagation value, specified by number (e.g. containe
r.mount.propagation[0]) or mount source (container.mount.propag
ation[/usr/local]). The pathname can be a glob.
container.image.repository
the container image repository (e.g. sysdig/sysdig).
container.image.tag
the container image tag (e.g. stable, latest).
container.image.digest
the container image registry digest (e.g. sha256:d977378f890d44
5c15e51795296e4e5062f109ce6da83e0a355fc4ad8699d27).
container.healthcheck
The container's health check. Will be the null value ("N/A") if
no healthcheck configured, "NONE" if configured but explicitly
not created, and the healthcheck command line otherwise
k8s Field Class
Fields to filter on Kubernetes metadata. Allows rules to apply to particular namespaces (k8s.ns.name) or a resource’s labels.
k8s.pod.name Kubernetes pod name.
k8s.pod.id Kubernetes pod id.
k8s.pod.label Kubernetes pod label. E.g. 'k8s.pod.label.foo'.
k8s.pod.labels Kubernetes pod comma-separated key/value labels. E.g. 'foo1:bar
1,foo2:bar2'.
k8s.rc.name Kubernetes replication controller name.
k8s.rc.id Kubernetes replication controller id.
k8s.rc.label Kubernetes replication controller label. E.g. 'k8s.rc.label.foo
'.
k8s.rc.labels Kubernetes replication controller comma-separated key/value lab
els. E.g. 'foo1:bar1,foo2:bar2'.
k8s.svc.name Kubernetes service name (can return more than one value, concat
enated).
k8s.svc.id Kubernetes service id (can return more than one value, concaten
ated).
k8s.svc.label Kubernetes service label. E.g. 'k8s.svc.label.foo' (can return
more than one value, concatenated).
k8s.svc.labels Kubernetes service comma-separated key/value labels. E.g. 'foo1
:bar1,foo2:bar2'.
k8s.ns.name Kubernetes namespace name.
k8s.ns.id Kubernetes namespace id.
k8s.ns.label Kubernetes namespace label. E.g. 'k8s.ns.label.foo'.
k8s.ns.labels Kubernetes namespace comma-separated key/value labels. E.g. 'fo
o1:bar1,foo2:bar2'.
k8s.rs.name Kubernetes replica set name.
k8s.rs.id Kubernetes replica set id.
k8s.rs.label Kubernetes replica set label. E.g. 'k8s.rs.label.foo'.
k8s.rs.labels Kubernetes replica set comma-separated key/value labels. E.g. '
foo1:bar1,foo2:bar2'.
k8s.deployment.name
Kubernetes deployment name.
k8s.deployment.id
Kubernetes deployment id.
k8s.deployment.label
Kubernetes deployment label. E.g. 'k8s.rs.label.foo'.
k8s.deployment.labels
Kubernetes deployment comma-separated key/value labels. E.g. 'f
oo1:bar1,foo2:bar2'.
mesos Field Class
Fields to filter on Mesosphere metadata such as application name, task, etc.
mesos.task.name Mesos task name.
mesos.task.id Mesos task id.
mesos.task.label
Mesos task label. E.g. 'mesos.task.label.foo'.
mesos.task.labels
Mesos task comma-separated key/value labels. E.g. 'foo1:bar1,fo
o2:bar2'.
mesos.framework.name
Mesos framework name.
mesos.framework.id
Mesos framework id.
marathon.app.name
Marathon app name.
marathon.app.id Marathon app id.
marathon.app.label
Marathon app label. E.g. 'marathon.app.label.foo'.
marathon.app.labels
Marathon app comma-separated key/value labels. E.g. 'foo1:bar1,
foo2:bar2'.
marathon.group.name
Marathon group name.
marathon.group.id
Marathon group id.
Kubernetes Audit Events (source k8s_audit)
Kubernetes Audit event fields are supported by the Kubernetes Audit event source. For more information please refer to the Kubernetes Audit event source documentation.
# Kubernetes Audit event Fields
$ falco --list=k8s_audit
jevt Field Class: generic ways to access json events
jevt.time json event timestamp as a string that includes the nanosecond p
art
jevt.rawtime absolute event timestamp, i.e. nanoseconds from epoch.
jevt.value General way to access single property from json object. The syn
tax is [<json pointer expression>]. The property is returned as
a string
jevt.obj The entire json object, stringified
ka Field Class: Access K8s Audit Log Events
ka.auditid The unique id of the audit event
ka.stage Stage of the request (e.g. RequestReceived, ResponseComplete, e
tc.)
ka.auth.decision
The authorization decision
ka.auth.reason The authorization reason
ka.user.name The user name performing the request
ka.user.groups The groups to which the user belongs
ka.impuser.name The impersonated user name
ka.verb The action being performed
ka.uri The request URI as sent from client to server
ka.uri.param The value of a given query parameter in the uri (e.g. when uri=
/foo?key=val, ka.uri.param[key] is val).
ka.target.name The target object name
ka.target.namespace
The target object namespace
ka.target.resource
The target object resource
ka.target.subresource
The target object subresource
ka.req.binding.subjects
When the request object refers to a cluster role binding, the s
ubject (e.g. account/users) being linked by the binding
ka.req.binding.subject.has_name
When the request object refers to a cluster role binding, retur
n true if a subject with the provided name exists
ka.req.binding.role
When the request object refers to a cluster role binding, the r
ole being linked by the binding
ka.req.configmap.name
If the request object refers to a configmap, the configmap name
ka.req.configmap.obj
If the request object refers to a configmap, the entire configm
ap object
ka.req.container.image
When the request object refers to a container, the container's
images. Can be indexed (e.g. ka.req.container.image[0]). Withou
t any index, returns the first image
ka.req.container.image.repository
The same as req.container.image, but only the repository part (
e.g. sysdig/falco)
ka.req.container.host_network
When the request object refers to a container, the value of the
hostNetwork flag.
ka.req.container.privileged
When the request object refers to a container, whether or not a
ny container is run privileged. With an index, return whether o
r not the ith container is run privileged.
ka.req.role.rules
When the request object refers to a role/cluster role, the rule
s associated with the role
ka.req.role.rules.apiGroups
When the request object refers to a role/cluster role, the api
groups associated with the role's rules. With an index, return
only the api groups from the ith rule. Without an index, return
all api groups concatenated
ka.req.role.rules.nonResourceURLs
When the request object refers to a role/cluster role, the non
resource urls associated with the role's rules. With an index,
return only the non resource urls from the ith rule. Without an
index, return all non resource urls concatenated
ka.req.role.rules.verbs
When the request object refers to a role/cluster role, the verb
s associated with the role's rules. With an index, return only
the verbs from the ith rule. Without an index, return all verbs
concatenated
ka.req.role.rules.resources
When the request object refers to a role/cluster role, the reso
urces associated with the role's rules. With an index, return o
nly the resources from the ith rule. Without an index, return a
ll resources concatenated
ka.req.service.type
When the request object refers to a service, the service type
ka.req.service.ports
When the request object refers to a service, the service's port
s. Can be indexed (e.g. ka.req.service.ports[0]). Without any i
ndex, returns all ports
ka.req.volume.hostpath
If the request object contains volume definitions, whether or n
ot a hostPath volume exists that mounts the specified path from
the host (...hostpath[/etc]=true if a volume mounts /etc from
the host). The index can be a glob, in which case all volumes a
re considered to find any path matching the specified glob (...
hostpath[/usr/*] would match either /usr/local or /usr/bin)
ka.resp.name The response object name
ka.response.code
The response code
ka.response.reason
The response reason (usually present only for failures)
Table of contents