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CADETS Trace Data

The current CADETS trace serialization format is an array of JSON event objects. A translator exists to convert this format into CDM.

Here is an example CADETS trace event:

[
  {
    "event": "audit:event:aue_openat_rwtc:",
    "time": 1487765664593158346,
    "pid": 8102,
    "ppid": 8101,
    "tid": 100414,
    "uid": 0,
    "exec": "sh",
    "subjprocuuid": "725a5534-f8f8-11e6-a0ed-44a8421f8dc6",
    "subjthruuid": "6daf2ce1-f879-11e6-a0ec-44a8421f8dc6",
    "arg_objuuid1": "9dbd8bea-f587-f65e-87f5-af32eef62ad7",
    "ret_objuuid1": "9dbd8bea-f587-f65e-87f5-af32eef62ad7",
    "upath1": "/usr/home/amanda/BasicOps.sh",
    "flags": 1048576,
    "fd": -100,
    "mode": 0,
    "retval": 3}
]

For each event, CADETS captures a variety of information.

Each event will have a subset of following attributes:

  • event: The event name. We use DTrace's naming convention for events (:::). For example, "audit:event:aue_open_rwtc:" is an event that is triggered when the FreeBSD open() system call is entered.
  • time: The time the event occurred expressed as nanoseconds since 00:00 Universal Coordinated Time, January 1, 1970.
  • pid: The ID of the process that generated the event. While there will be only one process with a given PID at a time, the PID may later be reused for another process.
  • subjprocuuid: A UUID of the process that generated the event. This will uniquely identify the process, unlike the PID.
  • subjthruuid: A UUID of the thread that generated the event.
  • ppid: The ID of the parent of the process that generated the event.
  • tid: The ID of the thread that generated the event.
  • uid: The ID of the user that generated the event.
  • exec: The name of the executable associated with this event.

Additionally, each event can have a subset of following attributes:

  • fd: A filesystem descriptor (fd) input (argument) associated with this event.
  • address: The IPv4/v6 address associated with an event.
  • port: The network port associated with an event.
  • arg_objuuid1: A UUID associated with an object that is an input (argument) to this event
  • upath1: A path input associated with the event.
  • arg_objuuid2: A UUID associated with a second object that is an input (argument) to this event
  • upath2: A second path input associated with the event.
  • ret_objuuid1: A UUID associated with an object that is an output (return value) of this event
  • ret_objuuid2: A UUID associated with a second object that is an output (return value) of this event
  • retval: A return value associated with the event. For filesystem calls, the retval often holds the file descriptor returned.
  • cmdline: captures the full command invocation
  • fdpath: a partial pathname for the file descriptor (fd) associated with reads, writes, mmaps. This attribute is not always present, and will often give only a partial path. UUIDs should be used for analysis as they are always available.

CDM Mapping

Our traces are converted to CDM format on a per event record basis. Currently, each event in a CADETS trace is converted to a corresponding event entry in the CDM format. If necessary, related objects are also created, such as files, users, or processes.

Take this short trace:

[
  {"event": "audit:event:aue_unlink:", "time": 1487790026874569660, "pid": 11476, "ppid": 11475, "tid": 100420, "uid": 0, "exec": "remove_file", "subjprocuuid": "2b8bd0cb-f931-11e6-a0f0-44a8421f8dc6", "subjthruuid": "ac7446db-f87c-11e6-a0ec-44a8421f8dc6", "arg_objuuid1": "6ce6eadb-4420-a159-a044-740359a11bdb", "upath1": "/usr/home/amanda/tc/trace-data/ripe_unit_tests/temp.out", "retval": 0}
, {"event": "audit:event:aue_exit:", "time": 1487790026874569660, "pid": 11476, "ppid": 11475, "tid": 100420, "uid": 0, "exec": "remove_file", "subjprocuuid": "2b8bd0cb-f931-11e6-a0f0-44a8421f8dc6", "subjthruuid": "ac7446db-f87c-11e6-a0ec-44a8421f8dc6", "retval": 0}
]

In CDM format, it looks like this remove_file.cdm.json. This simple trace becomes a graph with 2 events, a process, a principal, and a file object.

Events are converted to known CDM events when possible, and are otherwise left as EVENT_OTHER.

Any information from the CADETS trace that does not have a corresponding place in the CDM trace and may be useful is copied into the properties field as a map of fields to values.

File objects are created when they are first referenced. File objects are not defined by their paths. File names are given with the file objects on opens, but may not be included for reads or writes. Sometimes different paths will refer to the same file object, and sometimes the same path will refer to different file objects over time.

When a process starts executing a new program, the CDM trace will show the full path of the file being executed in the exec event.

For example:

{"datum": {"timestampMicros": 1469212271398110, "uuid": "00000000000000030000000000000019", "sequence": 25, "source": "SOURCE_FREEBSD_DTRACE_CADETS", "threadId": 100259, "type": "EVENT_EXECUTE", "properties": {"subjprocuuid": "76dd6962-503a-11e6-b8c7-080027889132", "arg_objuuid1": "c63c9e57-55b6-7d59-b655-e198f97d106e", "probe": "", "module": "event", "call": "aue_execve", "provider": "audit", "path": "/usr/local/bin/wget", "retval": "0", "upath1": "/usr/local/bin/wget"}}, "CDMVersion": "13"}
{"CDMVersion": "13", "datum": {"baseObject": {"source": "SOURCE_FREEBSD_DTRACE_CADETS", "properties": {}}, "uuid": "000000000000000649883dfd38c0a873", "url": "/usr/local/bin/wget", "isPipe": false, "version": 1, "properties": {}}}
{"CDMVersion": "13", "datum": {"fromUuid": "000000000000000649883dfd38c0a873", "toUuid": "00000000000000030000000000000019", "properties": {}, "timestamp": 1469212271398110, "type": "EDGE_FILE_AFFECTS_EVENT"}}

Identifying SSH Sessions

When analysing traces, it may be useful to identify separate SSH sessions as well as identifying the IP address initiating the connection. Reads and writes from /dev/tty or /dev/pts/* indicate the data came from a console.

The read and write events do not provide enough information by themselves to identify the IP address, however, by tracing the process and its parent processes back to the initial ssh connection, the IP address can be identified. A connection from the relevant IP address is accepted, and other connections are also made using connect (only the accept syscall is shown below).

Unfortunately, ssh forks numerous times, so it may take traversing a number of links to locate the IP address.

In the sample below, the ssh session was initiated from 192.168.1.1. I can determine that by starting with the read event, finding the process running it (5c1274b56ec811e693e844a8421f8dc6), finding its parent process (5a1260586ec811e693e844a8421f8dc6), and its parent process (68436e4258c411e6937744a8421f8dc6). This process is the ssh daemon. Looking at this process I can see that it accepted a connection from 192.168.1.1 and then quickly forked off the process chain that I just followed. The ssh processes forked also connected to 192.168.1.1 numerous times.

Note that this sample was generated and then modified by hand to improve readability - it is not exactly what would be generated.

{"datum": {"properties": {}, "uuid": "68436e4258c411e6937744a8421f8dc6", "pid": 868, "type": "SUBJECT_PROCESS", "ppid": 1, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "CDMVersion": "13"}
...
{"datum": {"properties": {"address": "192.168.1.1", "subjprocuuid": "68436e4258c411e6937744a8421f8dc6", "port": "29348", "arg_objuuid1": "6843b94f58c411e6937744a8421f8dc6", "exec": "sshd", "call": "aue_accept", "retval": "5", "fd": "4", "arg_objuuid2": "5a1220326ec811e693e844a8421f8dc6"}, "uuid": "e1c8ad6c29ba56e68173f74644aa9e55", "timestampMicros": 1472571746503006, "threadId": 100094, "type": "EVENT_ACCEPT", "source": "SOURCE_FREEBSD_DTRACE_CADETS", "sequence": 0}, "CDMVersion": "13"}
{"datum": {"properties": {}, "srcPort": -1, "destAddress": "192.168.1.1", "srcAddress": "localhost", "uuid": "357a3fc1a1855ff2ad9d57376aada9c8", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "destPort": 29348}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "e1c8ad6c29ba56e68173f74644aa9e55", "toUuid": "357a3fc1a1855ff2ad9d57376aada9c8", "type": "EDGE_EVENT_AFFECTS_NETFLOW", "timestamp": 1472571746503006}, "CDMVersion": "13"}
...
{"datum": {"properties": {"subjprocuuid": "68436e4258c411e6937744a8421f8dc6", "exec": "sshd", "ret_objuuid1": "5a1260586ec811e693e844a8421f8dc6", "call": "aue_fork", "retval": "5334", "arg_pid": "5334", "ret_objuuid2": "5a1260586ec811e693e844a8421f8dc6"}, "uuid": "d1d6679cdd475179908ef14018be1c6a", "timestampMicros": 1472571746503878, "threadId": 100094, "type": "EVENT_FORK", "source": "SOURCE_FREEBSD_DTRACE_CADETS", "sequence": 1}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "d1d6679cdd475179908ef14018be1c6a", "toUuid": "68436e4258c411e6937744a8421f8dc6", "type": "EDGE_EVENT_ISGENERATEDBY_SUBJECT", "timestamp": 1472571746503878}, "CDMVersion": "13"}
{"datum": {"properties": {}, "uuid": "5a1260586ec811e693e844a8421f8dc6", "pid": 5334, "type": "SUBJECT_PROCESS", "ppid": 868, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "5a1260586ec811e693e844a8421f8dc6", "toUuid": "68436e4258c411e6937744a8421f8dc6", "type": "EDGE_SUBJECT_HASPARENT_SUBJECT", "timestamp": 1472571746503878}, "CDMVersion": "13"}
...
{"datum": {"properties": {"subjprocuuid": "5a1260586ec811e693e844a8421f8dc6", "exec": "sshd", "ret_objuuid1": "5c1274b56ec811e693e844a8421f8dc6", "call": "aue_fork", "retval": "5337", "arg_pid": "5337", "ret_objuuid2": "5c1274b56ec811e693e844a8421f8dc6"}, "uuid": "986e989b2fd55b56a996de49648b3e72", "timestampMicros": 1472571749859869, "threadId": 100188, "type": "EVENT_FORK", "source": "SOURCE_FREEBSD_DTRACE_CADETS", "sequence": 2}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "986e989b2fd55b56a996de49648b3e72", "toUuid": "5a1260586ec811e693e844a8421f8dc6", "type": "EDGE_EVENT_ISGENERATEDBY_SUBJECT", "timestamp": 1472571749859869}, "CDMVersion": "13"}
{"datum": {"properties": {}, "uuid": "5c1274b56ec811e693e844a8421f8dc6", "pid": 5337, "type": "SUBJECT_PROCESS", "ppid": 5334, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "5c1274b56ec811e693e844a8421f8dc6", "toUuid": "5a1260586ec811e693e844a8421f8dc6", "type": "EDGE_SUBJECT_HASPARENT_SUBJECT", "timestamp": 1472571749859869}, "CDMVersion": "13"}
...
{"datum": {"properties": {"upath1": "/dev/tty", "subjprocuuid": "5c1274b56ec811e693e844a8421f8dc6", "exec": "sshd", "ret_objuuid1": "c0e6049062be7b5abe626f2dba7ba087", "fd": "-100", "call": "aue_openat_rwtc", "retval": "11", "flags": "1", "mode": "0", "arg_objuuid1": "c0e6049062be7b5abe626f2dba7ba087"}, "uuid": "2963b6532a405451b63d6c17688029f5", "timestampMicros": 1472571749998870, "threadId": 100075, "type": "EVENT_OPEN", "source": "SOURCE_FREEBSD_DTRACE_CADETS", "sequence": 4}, "CDMVersion": "13"}
{"datum": {"isPipe": false, "properties": {}, "version": 1, "uuid": "c0e6049062be7b5abe626f2dba7ba087", "url": "/dev/tty", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "c0e6049062be7b5abe626f2dba7ba087", "toUuid": "2963b6532a405451b63d6c17688029f5", "type": "EDGE_FILE_AFFECTS_EVENT", "timestamp": 1472571749998870}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "2963b6532a405451b63d6c17688029f5", "toUuid": "5c1274b56ec811e693e844a8421f8dc6", "type": "EDGE_EVENT_ISGENERATEDBY_SUBJECT", "timestamp": 1472571749998870}, "CDMVersion": "13"}
{"datum": {"properties": {"cmdline": "-bash", "subjprocuuid": "5c1274b56ec811e693e844a8421f8dc6", "exec": "sshd", "arg_objuuid1": "142d3f01803f0351bf809481b103bfc8", "upath1": "/usr/local/bin/bash", "call": "aue_execve", "retval": "0"}, "uuid": "6336246134a6559fa57cdf91b3184cb7", "timestampMicros": 1472571750007870, "threadId": 100075, "type": "EVENT_EXECUTE", "source": "SOURCE_FREEBSD_DTRACE_CADETS", "sequence": 5}, "CDMVersion": "13"}
{"datum": {"isPipe": false, "properties": {}, "version": 1, "uuid": "142d3f01803f0351bf809481b103bfc8", "url": "/usr/local/bin/bash", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "142d3f01803f0351bf809481b103bfc8", "toUuid": "6336246134a6559fa57cdf91b3184cb7", "type": "EDGE_FILE_AFFECTS_EVENT", "timestamp": 1472571750007870}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "6336246134a6559fa57cdf91b3184cb7", "toUuid": "5c1274b56ec811e693e844a8421f8dc6", "type": "EDGE_EVENT_ISGENERATEDBY_SUBJECT", "timestamp": 1472571750007870}, "CDMVersion": "13"}
{"datum": {"properties": {}, "fromUuid": "5c1274b56ec811e693e844a8421f8dc6", "toUuid": "a0641a9b43305c75aa889c78da0a0a36", "type": "EDGE_SUBJECT_HASLOCALPRINCIPAL", "timestamp": 1472571750007870}, "CDMVersion": "13"}
{"datum": {"properties": {"subjprocuuid": "5c1274b56ec811e693e844a8421f8dc6", "exec": "bash", "arg_objuuid1": "c0e6049062be7b5abe626f2dba7ba087", "fd": "0", "retval": "1", "fdpath": "/dev/tty", "call": "aue_read"}, "uuid": "2164220f8c555a0ebc7ce75a3fc5416f", "timestampMicros": 1472571751238024, "threadId": 100075, "type": "EVENT_READ", "source": "SOURCE_FREEBSD_DTRACE_CADETS", "sequence": 6}, "CDMVersion": "13"}

Another possibility is trying to isolate events in one of two ssh sessions. Again, it is possible to track back the parent processes and use that, but that is not the only option. While both will read and write from /dev/tty, the uuids will be different, and sometimes the pseudo-terminal path will be given instead of /dev/tty.

{"datum": {"url": "/dev/pts/1", "uuid": "c0e6049062be7b5abe626f2dba7ba087", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "properties": {}, "isPipe": false, "version": 1}, "CDMVersion": "13"}
{"datum": {"url": "/dev/tty", "uuid": "c0e6049062be7b5abe626f2dba7ba087", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "properties": {}, "isPipe": false, "version": -1}, "CDMVersion": "13"}
{"datum": {"url": "", "uuid": "c0e6049062be7b5abe626f2dba7ba087", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "properties": {}, "isPipe": false, "version": 2}, "CDMVersion": "13"}

{"datum": {"url": "/dev/pts/2", "uuid": "64ee4b938566e751a68583ede1e76e1a", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "properties": {}, "isPipe": false, "version": 1}, "CDMVersion": "13"}
{"datum": {"url": "/dev/tty", "uuid": "64ee4b938566e751a68583ede1e76e1a", "baseObject": {"properties": {}, "source": "SOURCE_FREEBSD_DTRACE_CADETS"}, "properties": {}, "isPipe": false, "version": -1}, "CDMVersion": "13"}

Traces

Currently, we are sharing traces that instrument the following events:

  • Filesystem events (e.g., open, close, dup, read, write)
  • Process events (e.g., fork, exec, exit)
  • Network events (e.g., connect, accept)
  • SSH login events
  • BuildInject scenario