diff options
| -rw-r--r-- | sec-blueprint/08-Hardening.md | 103 |
1 files changed, 0 insertions, 103 deletions
diff --git a/sec-blueprint/08-Hardening.md b/sec-blueprint/08-Hardening.md index 092eb74..dfd860f 100644 --- a/sec-blueprint/08-Hardening.md +++ b/sec-blueprint/08-Hardening.md @@ -424,17 +424,6 @@ Kernel Hardening ```bash CONFIG_SWAP=n -``` - -### Disable namespace support - - Do not allow namespace support to prevent duplicates of dev nodes, - pids and mount points. - This may be used in virtualization and container solutions like LXC, so in some cases it cannot be disabled. - -```bash - CONFIG_NAMESPACES=n -``` ### Disable NFS file system @@ -551,19 +540,6 @@ Kernel Hardening command line. All of the console=<interface> statements should be stripped and removed from the kernel command line. -- The following lines from /etc/inittab should be removed for the - serial console: - - S0:12345:respawn:/sbin/getty 115200 ttyS0 - - ttyS0::askfirst:-/bin/sh - - Failing to do so will result in the System V init process trying to - infinitely open a tty port and spawn a login shell on the serial - console, which will result in the following repetitive output: - - INIT: Id “S0” respawning too fast: disabled for 5 minutes - - The telnet server shall be disabled. - Do not start telnetd in init scripts. @@ -863,7 +839,6 @@ Kernel Hardening | Kernel Configuration | Kernel Version | |---------------------------------------|----------------| -| CONFIG\_CHECKPOINT\_RESTORE=n |3.3+ | | CONFIG\_UNIX\_DIAG=n |3.3+ | | CROSS\_MEMORY\_ATTACH=n |3.5+ | | CONFIG\_PANIC\_ON\_OOPS=y |3.5+ | @@ -995,18 +970,6 @@ Kernel Hardening BPF_JIT=n ``` -### Disable checkpoint/restore - - The checkpoint/restore service can take a process, freeze it and - migrate it. - This results in providing more info than a core dump. - This configuration is supported in Linux 3.3 and greater and thus should - only be disabled for such versions. - -```bash - CONFIG_CHECKPOINT_RESTORE=n -``` - ### Enable Enforced Module Signing This configuration is supported in Linux 3.7 and greater and thus @@ -1119,7 +1082,6 @@ respective environment. | Dropbear | Remove “dropbear” from ‘/etc/init.d/rcs’ | EXCLUDE | EXCLUDE | | SSH | NA | EXCLUDE | EXCLUDE | | Editors (vi) | /bin/vi | INCLUDE | EXCLUDE | -| Netstat | /bin/netstat | INCLUDE | EXCLUDE | | Dmesg | /bin/dmesg | INCLUDE | EXCLUDE | | UART | /proc/tty/driver/ | INCLUDE | EXCLUDE | | Hexdump | /bin/hexdump | INCLUDE | EXCLUDE | @@ -1265,71 +1227,6 @@ Network Hardening SYN requests with the appropriate SYN+ACK reply, but it does not store the connection in its backlog queue. -### Enable Iptables (firewall) - - Iptables is used to set up, maintain, and inspect the tables of IPv4 - packet filter rules in the Linux kernel. Iptables rules should be set - in such a way that it allows packets from authorized peer only. - - Following are the rules recommended until new features are implemented - on the STB. The rules are to be in the following sequence as iptables - works based on the sequencing of the rules. - - 1\) Allow only incoming UDP/TCP DNS packets only. These rules are only - applicable if the device needs to resolve DNS. If the device does not - need to resolve DNS then remove these. -``` - iptables -A INPUT -p udp --sport 53 -j ACCEPT - iptables -A INPUT -p udp --dport 53 -j ACCEPT - iptables -A INPUT -p tcp --sport 53 -j ACCEPT - iptables -A INPUT -p tcp --dport 53 -j ACCEPT -``` - - 2\) Allow only outgoing UDP/TCP DNS only - -``` - Iptables -A OUTPUT -p udp --sport 53 -j ACCEPT - iptables -A OUTPUT -p udp --dport 53 -j ACCEPT - iptables -A OUTPUT -p udp --sport 53 -j ACCEPT - iptables -A OUTPUT -p udp --dport 53 -j ACCEPT -``` - - 3\) Allow output UDP connection only for the audience measurement system -``` - iptables -I OUTPUT -p udp –sport 46251 -j ACCEPT -``` - - 4\) Drop all ICMP - -``` - iptables -A INPUT -p ICMP –icmp-type <all> -j DROP -``` - - 5\) Drop all forwarding packet - -``` - iptables -P FORWARD DROP -``` - - 6\) Drop all the TCP connections where SYN flag is unset and state is - NEW. -``` - iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP -``` - - 7\) Drop all the remaining TCP or UDP packets unknown to the STB - -``` - iptables -A INPUT -j DROP - iptables -A OUTPUT -j DROP -``` - - 8\) Drop all broadcast or multicast packets - -``` - iptables -A INPUT -m pkttype --pkt-type broadcast -j DROP - iptables -A INPUT -m pkttype --pkt-type multicast -j DROP -``` Validation ========== |