Correlate network connections with community ID in osquery.

Connect network monitoring with endpoint monitoring.

Interested in correlating events from network monitoring tools to host activity? Support for Community ID hashing in osquery allows osquery’s endpoint instrumentation to be easily correlated with that of network monitors such as Zeek. Similar strategies can be used to correlate osquery logs with those from other tools that support Community ID. This includes Arkime (formerly Moloch), Suricata, and more.

Community ID

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.

Correlation

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    13.227.76.23    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    13.227.76.89    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 172.17.0.2:42716 and 13.227.76.23:443. Looking in the last column of the log, we retrieve the Community ID 1:l7a9beh8+bQe2MRtUW92OFmMMsM=.

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 local_address AND remote_address AND 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 = 13.227.76.23
        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 process (start_time), and much more.

In this case we clearly observe that the network connection is a connection made with the netcat tool to osquery.io.

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 local_address AND remote_address AND 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

Extend the Concept

In the above examples, a live investigation of the network traffic is performed using osqueryi. How can we take advantage of this functionality to perform retroactive analysis?

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)

The community_id column can then be used to correlate the events logged by network monitors.

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 execution.