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-3-2-7.yml b/metadata/service/system/cis/cis-3-2-7.yml
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+# 3.2.7 Ensure Reverse Path Filtering is enabled
+#
+# Description
+# ===========
+# Setting net.ipv4.conf.all.rp_filter and net.ipv4.conf.default.rp_filter to 1
+# forces the Linux kernel to utilize reverse path filtering on a received
+# packet to determine if the packet was valid. Essentially, with reverse path
+# filtering, if the return packet does not go out the same interface that the
+# corresponding source packet came from, the packet is dropped (and logged if
+# log_martians is set).
+#
+# Rationale
+# =========
+# Setting these flags is a good way to deter attackers from sending your system
+# bogus packets that cannot be responded to. One instance where this feature
+# breaks down is if asymmetrical routing is employed. This would occur when
+# using dynamic routing protocols (bgp, ospf, etc) on your system. If you are
+# using asymmetrical routing on your system, you will not be able to enable
+# this feature without breaking the routing.
+#
+# Audit
+# =====
+#
+# Run the following commands and verify output matches:
+#
+# # sysctl net.ipv4.conf.all.rp_filter
+# net.ipv4.conf.all.rp_filter = 1
+# # sysctl net.ipv4.conf.default.rp_filter
+# net.ipv4.conf.default.rp_filter = 1
+#
+# Remediation
+# ===========
+#
+# Set the following parameters in the /etc/sysctl.conf file:
+#
+# net.ipv4.conf.all.rp_filter = 1
+# net.ipv4.conf.default.rp_filter = 1
+#
+# Run the following commands to set the active kernel parameters:
+#
+# # sysctl -w net.ipv4.conf.all.rp_filter=1
+# # sysctl -w net.ipv4.conf.default.rp_filter=1
+# # sysctl -w net.ipv4.route.flush=1
+
+parameters:
+ linux:
+ system:
+ kernel:
+ sysctl:
+ net.ipv4.conf.all.rp_filter: 1
+ net.ipv4.conf.default.rp_filter: 1