Persistence (TA0003)(opens in a new tab or window)
sequence by host.id with maxspan=1s
[process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
process.parent.executable == "/usr/sbin/sshd"] by process.entity_id
[network where host.os.type == "linux" and event.type == "start" and event.action == "connection_attempted" and not (
destination.ip == null or destination.ip == "0.0.0.0" or cidrmatch(
destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29",
"192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
"192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10",
"192.175.48.0/24","198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10",
"FF00::/8", "172.31.0.0/16"
)
) and not (
process.executable in ("/bin/yum", "/usr/bin/yum") or
process.name in ("login_duo", "ssh", "sshd", "sshd-session")
)
] by process.parent.entity_id
Install detection rules in Elastic Security
Detect Network Connection Initiated by SSHD Child Process in the Elastic Security detection engine by installing this rule into your Elastic Stack.
To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).