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ssh.bro
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ssh.bro
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@load ./main
@load base/utils/directions-and-hosts
@load base/protocols/ssh
module Netbase;
export {
redef record Netbase::observation += {
# SSH Stats
ssh_auth_fail_sent: count &default=0 &log;
ssh_auth_fail_recvd: count &default=0 &log;
ssh_as_client: count &default=0 &log;
ssh_as_server: count &default=0 &log;
};
}
# Collect ssh auth failure stats
event ssh_auth_failed(c: connection)
{
local orig = c$id$orig_h;
local resp = c$id$resp_h;
local pkg = observables();
if ( addr_matches_host(orig, LOCAL_HOSTS) )
{
pkg[orig] = set([$name="ssh_auth_fail_recvd"]);
}
if ( addr_matches_host(resp, LOCAL_HOSTS) )
{
pkg[resp] = set([$name="ssh_auth_fail_sent"]);
}
# See if the observable pkgs need delivering
if ( orig in pkg )
{
Netbase::SEND(orig, pkg[orig]);
}
if ( resp in pkg )
{
Netbase::SEND(resp, pkg[resp]);
}
}
# Handle auth success events to track when hosts are acting as
# as ssh clients and servers.
event ssh_auth_successful(c: connection, auth_method_none: bool)
{
local orig = c$id$orig_h;
local resp = c$id$resp_h;
local pkg = observables();
if ( addr_matches_host(orig, LOCAL_HOSTS) )
{
pkg[orig] = set([$name="ssh_as_client"]);
}
if ( addr_matches_host(resp, LOCAL_HOSTS) )
{
pkg[resp] = set([$name="ssh_as_server"]);
}
# See if the observable pkgs need delivering
if ( orig in pkg )
{
Netbase::SEND(orig, pkg[orig]);
}
if ( resp in pkg )
{
Netbase::SEND(resp, pkg[resp]);
}
}
# Handler to load observables into the observations table
# This event is executed every time a node calls the SEND()
# function.
@if ( ! Cluster::is_enabled() || Cluster::local_node_type() == Cluster::PROXY )
event Netbase::add_observables(ip: addr, obs: set[observable])
{
for ( o in obs )
{
switch o$name
{
case "ssh_auth_fail_recvd":
++observations[ip]$ssh_auth_fail_recvd;
break;
case "ssh_auth_fail_sent":
++observations[ip]$ssh_auth_fail_sent;
break;
case "ssh_as_client":
++observations[ip]$ssh_auth_fail_recvd;
break;
case "ssh_as_server":
++observations[ip]$ssh_auth_fail_sent;
break;
}
}
}
@endif