Interested in correlating events from network monitoring tools to host activity? Support for Community ID hashing in osquery 4.2.0 allows osquery’s endpoint instrumentation to be easily correlated with that of network monitors such as Zeek (formerly Bro). Similar strategies can be used to correlate osquery logs with those from other tools that support Community ID. This includes Moloch, Suricata, and more.
Community ID is a hash of the network connection parameters that allows a connection to be matched between monitoring solutions that support the hash.
To generate a Community ID, a hash is performed with the source and destination IP addresses and ports, along with the protocol and a seed. The generated hash is deterministic and can be compared across implementing software.
How do we use Community ID to correlate the logs between a networking tool and
osquery? Consider the following
conn.log generated by Zeek:
$ cat /usr/local/zeek/logs/current/conn.log ... #fields ts uid id.orig_h id.orig_p id.resp_h id.resp_p proto service duration orig_bytes resp_bytes conn_state local_orig local_resp missed_bytes history orig_pkts orig_ip_bytes resp_pkts resp_ip_bytes tunnel_parents community_id #types time string addr port addr port enum string interval count count string bool bool count string count count count count set[string] string 1582669704.509068 CEmnOh4OZTnzaUHWi 172.17.0.2 47434 192.168.65.1 53 udp dns 0.030783 0 36 SHR T T 0 Cd 0 0 164 - 1:M9OoSr2um69x5G8SikO3S7CVlKk= 1582669709.819653 CVTuEs4iasnpIw8nb7 172.17.0.2 35173 192.168.65.1 53 udp dns 0.004224 0 92 SHR T T 0 Cd 0 0 1120 - 1:1/6GSKCm6A8zk8jXFOEeZKTYccY= 1582669709.844549 CZX3af2jpkfeJzNItb 172.17.0.2 42716 188.8.131.52 443 tcp - 30.017714 0 0 SHR T F 0 ^hCf 0 0 288 - 1:l7a9beh8+bQe2MRtUW92OFmMMsM= 1582669741.641209 CQFgp24cLxMDaBPr03 172.17.0.2 50944 184.108.40.206 443 tcp - 1.691777 0 9653625 SHR T F 0 ^hCadCCCfA 1 406827 9926713 - 1:13GuW4mT6PnRwUi+zetPtsWWD3I= 1582669741.587538 CDvjoz2xAkMs4vbpo8 172.17.0.2 38330 192.168.65.1 53 udp dns 0.033607 0 352 SHR T T 0 Cd 0 0 2408 - 1:6tMXxnnFDfuiCIYTYXXCPMfB3fA=
Say that we are interested in the TCP connection between
220.127.116.11:443. Looking in the last column of the log, we retrieve the
We can now use the Community ID as the connection to the information available in osquery:
osquery> SELECT community_id_v1(local_address,remote_address,local_port,remote_port,protocol) AS community_id, * ...> FROM processes JOIN process_open_sockets USING (pid) ...> WHERE community_id = '1:l7a9beh8+bQe2MRtUW92OFmMMsM='; community_id = 1:l7a9beh8+bQe2MRtUW92OFmMMsM= pid = 23689 name = nc path = /bin/nc.traditional cmdline = nc osquery.io 443 state = T cwd = /root root = / uid = 0 gid = 0 euid = 0 egid = 0 suid = 0 sgid = 0 on_disk = 1 wired_size = 0 resident_size = 2088000 total_size = 10880000 user_time = 0 system_time = 0 disk_bytes_read = 0 disk_bytes_written = 0 start_time = 1582669708 parent = 1 pgroup = 23689 threads = 1 nice = 0 fd = 3 socket = 138425 family = 2 protocol = 6 local_address = 172.17.0.2 remote_address = 18.104.22.168 local_port = 42716 remote_port = 443 path = state = CLOSE_WAIT net_namespace = 4026532309
This query provides a great deal more context for the network connection
observed in Zeek. We can see what command is running (
cmdline), the path to
the executable (
path), the executing user (
uid), the start time of the
start_time), and much more.
In this case we clearly observe that the network connection is a connection made
netcat tool to
The data retrieved by osquery can be further extended by joining to additional tables. For example, the following query also retrieves the MD5 hash of the process binary:
osquery> SELECT pid, processes.path, cmdline, md5 ...> FROM processes JOIN process_open_sockets USING (pid) JOIN hash USING (path) ...> WHERE community_id_v1(local_address,remote_address,local_port,remote_port,protocol) = '1:l7a9beh8+bQe2MRtUW92OFmMMsM='; pid = 23689 path = /bin/nc.traditional cmdline = nc osquery.io 443 md5 = 1c50c85a1472d0124194f21a12ade35e
In the above examples, a live investigation of the network traffic is performed
osqueryi. How can we take advantage of this functionality to perform
Queries can be scheduled within
osqueryd to log the Community ID of network
connections along with the details about the associated process. These logs can
be collected in the log aggregation pipeline/SIEM and correlated with the logs
from network monitoring. Consider scheduling queries such as:
SELECT *, community_id_v1(local_address,remote_address,local_port,remote_port,protocol) AS community_id FROM processes JOIN process_open_sockets USING (pid) JOIN hash USING (path)
community_id column can then be used to correlate the events logged by
On Linux, the
socket_events table may produce additional utility as it
captures all socket connections, not only those active at the time of query
Thank you to Security Onion Solutions for sponsoring Dactiv’s development of this new feature in osquery.