TMA-OCI-2.3

Ensure no network security groups allow ingress from 0.0.0.0/0 to port 22

HighLevel 1Automatedoci

Description

Network security groups provide stateful filtering of ingress/egress network traffic to OCI resources. It is recommended that no security group allows unrestricted ingress to port 22. Removing unfettered connectivity to remote console services, such as Secure Shell (SSH), reduces a server's exposure to risk. Flags network security groups with an INGRESS rule from 0.0.0.0/0 covering port 22. Covers every subscribed region and every accessible compartment. Read-only OCI CLI calls; credentials and home region come from the CLI's normal configuration (~/.oci/config, OCI_CLI_PROFILE, OCI_CLI_AUTH). The tenancy OCID is taken from OCI_TENANCY or the first tenancy= line of the config file. A missing CLI or credential fails the check.

How it is checked

Audit method: Shell command

shell

t=${OCI_TENANCY:-$(sed -n 's/^[[:space:]]*tenancy[[:space:]]*=[[:space:]]*//p' "${OCI_CLI_CONFIG_FILE:-$HOME/.oci/config}" 2>/dev/null | head -n 1 | tr -d '\r[:space:]')}
[ -n "$t" ] || exit 1
bad=0
cs=$(oci iam compartment list --compartment-id "$t" --compartment-id-in-subtree true --access-level ACCESSIBLE --all --query 'data[?"lifecycle-state"==`"ACTIVE"`].id' --raw-output 2>/dev/null) || exit 1
comps="$t $(printf '%s\n' "$cs" | grep -o 'ocid1\.compartment\.[^"]*')"
rs=$(oci iam region-subscription list --tenancy-id "$t" --query 'data[?status==`"READY"`]."region-name"' --raw-output 2>/dev/null) || exit 1
regions=$(printf '%s\n' "$rs" | grep -o '"[a-z0-9-]*"' | tr -d '"')
[ -n "$regions" ] || exit 1
for r in $regions; do
  for c in $comps; do
    ns=$(oci network nsg list --compartment-id "$c" --region "$r" --all --query 'data[?"lifecycle-state"==`"AVAILABLE"`].id' --raw-output 2>/dev/null) || exit 1
    for g in $(printf '%s\n' "$ns" | grep -o 'ocid1\.networksecuritygroup\.[^"]*'); do
      n=$(oci network nsg rules list --nsg-id "$g" --region "$r" --all --query 'length(data[?direction==`"INGRESS"` && (source==`"0.0.0.0/0"`) && (protocol==`"all"` || (protocol==`"6"` && ("tcp-options"."destination-port-range"==`null` || ("tcp-options"."destination-port-range".min<=`22` && "tcp-options"."destination-port-range".max>=`22`))) || (protocol==`"17"` && ("udp-options"."destination-port-range"==`null` || ("udp-options"."destination-port-range".min<=`22` && "udp-options"."destination-port-range".max>=`22`))))])' --raw-output 2>/dev/null) || exit 1
      [ "${n:-0}" -eq 0 ] || { echo "port 22 open to 0.0.0.0/0: $r $g"; bad=1; }
    done
  done
done
[ "$bad" -eq 0 ] && echo compliant

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Remove or narrow the offending NSG rules (oci network nsg rules remove / update --nsg-id <ocid> ...) so 0.0.0.0/0 cannot reach port 22.

Properties

Operating systems: Any
Tags: ocinetwork
Reference: CIS Oracle Cloud Infrastructure Foundations Benchmark v3.1.1 - 2.3 Ensure no network security groups allow ingress from 0.0.0.0/0 to port 22

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target oci