CIS compliance (sysctl, limits)
* CIS 1.5.1 Ensure core dumps are restricted
* CIS 1.5.3 Ensure address space layout randomization (ASLR) is enabled
* CIS 3.1.2 Ensure packet redirect sending is disabled
* CIS 3.2.1 Ensure source routed packets are not accepted
* CIS 3.2.2 Ensure ICMP redirects are not accepted
* CIS 3.2.3 Ensure secure ICMP redirects are not accepted
* CIS 3.2.4 Ensure suspicious packets are logged
* CIS 3.2.5 Ensure broadcast ICMP requests are ignored
* CIS 3.2.6 Ensure bogus ICMP responses are ignored
* CIS 3.2.7 Ensure Reverse Path Filtering is enabled
* CIS 3.2.8 Ensure TCP SYN Cookies is enabled
All sysctls are valid for Ubuntu 14.04, Ubuntu 16.04.
Change-Id: I48f34c55d97a78c253d4810db46b2a04ff5c0c1a
diff --git a/metadata/service/system/cis/cis-3-2-5.yml b/metadata/service/system/cis/cis-3-2-5.yml
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+# 3.2.5 Ensure broadcast ICMP requests are ignored
+#
+# Description
+# ===========
+# Setting net.ipv4.icmp_echo_ignore_broadcasts to 1 will cause the
+# system to ignore all ICMP echo and timestamp requests to broadcast
+# and multicast addresses.
+#
+# Rationale
+# =========
+# Accepting ICMP echo and timestamp requests with broadcast or multicast
+# destinations for your network could be used to trick your host into starting
+# (or participating) in a Smurf attack. A Smurf attack relies on an attacker
+# sending large amounts of ICMP broadcast messages with a spoofed source
+# address. All hosts receiving this message and responding would send
+# echo-reply messages back to the spoofed address, which is probably not
+# routable. If many hosts respond to the packets, the amount of traffic on
+# the network could be significantly multiplied.
+#
+# Audit
+# =====
+#
+# Run the following commands and verify output matches:
+#
+# # sysctl net.ipv4.icmp_echo_ignore_broadcasts
+# net.ipv4.icmp_echo_ignore_broadcasts = 1
+#
+# Remediation
+# ===========
+#
+# Set the following parameter in the /etc/sysctl.conf file:
+#
+# net.ipv4.icmp_echo_ignore_broadcasts = 1
+#
+# Run the following commands to set the active kernel parameters:
+#
+# # sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
+# # sysctl -w net.ipv4.route.flush=1
+
+parameters:
+ linux:
+ system:
+ kernel:
+ sysctl:
+ net.ipv4.icmp_echo_ignore_broadcasts: 1