From 5f8f98024f8955a0327b67f873923757a51d082c Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Tue, 19 Jan 2021 12:32:07 +0100 Subject: [PATCH 1/7] add rule and remediations --- .../ansible/shared.yml | 13 +++++ .../bash/shared.sh | 7 +++ .../oval/shared.xml | 38 +++++++++++++ .../rule.yml | 57 +++++++++++++++++++ 5 files changed, 115 insertions(+), 1 deletion(-) create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/ansible/shared.yml create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/rule.yml diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/ansible/shared.yml b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/ansible/shared.yml new file mode 100644 index 0000000000..cefba7db05 --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/ansible/shared.yml @@ -0,0 +1,13 @@ +# platform = Red Hat Enterprise Linux 7,Oracle Linux 7 +# reboot = false +# strategy = restrict +# complexity = low +# disruption = low + +- name: "Configure sshd to use approved MACs" + lineinfile: + path: /etc/ssh/sshd_config + line: 'MACs hmac-sha2-512,hmac-sha2-256' + state: present + regexp: '^[\s]*MACs[\s]+(hmac-sha2-512(?=[\w,-@]+|$),?)?(hmac-sha2-256(?=[\w,-@]+|$),?)?[\s]*(?:#.*)?$' + create: True diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh new file mode 100644 index 0000000000..c76190fb96 --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh @@ -0,0 +1,7 @@ +# platform = multi_platform_wrlinux,Red Hat Enterprise Linux 7,Oracle Linux 7 + +if grep -q -P '^[[:space:]]*MACs[[:space:]]+' /etc/ssh/sshd_config; then + sed -i 's/^\s*MACs.*/MACs hmac-sha2-512,hmac-sha2-256/' /etc/ssh/sshd_config +else + echo "MACs hmac-sha2-512,hmac-sha2-256" >> /etc/ssh/sshd_config +fi diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml new file mode 100644 index 0000000000..d7fbd9f0ed --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml @@ -0,0 +1,38 @@ + + + {{{ oval_metadata("Limit the Message Authentication Codes (MACs) to those which are FIPS-approved.") }}} + + + + + + + + + + + + + + + + + + + + + + /etc/ssh/sshd_config + ^[\s]*(?i)MACs(?-i)[\s]+(?=[\w,-@]+)(hmac-sha2-512(?=[\w,-@]+|$),?)?(hmac-sha2-256(?=[\w,-@]+|$),?)?[\s]*(?:#.*)?$ + 1 + + + diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/rule.yml b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/rule.yml new file mode 100644 index 0000000000..dc9f7dca7c --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/rule.yml @@ -0,0 +1,57 @@ +documentation_complete: true + +prodtype: rhel7 + +title: 'Use Only FIPS 140-2 Validated MACs' + +description: |- + Limit the MACs to those hash algorithms which are FIPS-approved. + The following line in /etc/ssh/sshd_config + demonstrates use of FIPS-approved MACs: + 
MACs hmac-sha2-512,hmac-sha2-256
+ This rule ensures that there are configured MACs mentioned + above (or their subset), keeping the given order of algorithms. + +rationale: |- + DoD Information Systems are required to use FIPS-approved cryptographic hash + functions. The only SSHv2 hash algorithms meeting this requirement is SHA2. + +severity: medium + +identifiers: + cce@rhel7: CCE-83398-8 + +references: + disa: CCI-000068,CCI-000803,CCI-000877,CCI-001453,CCI-003123 + srg: SRG-OS-000125-GPOS-00065,SRG-OS-000250-GPOS-00093,SRG-OS-000394-GPOS-00174 + stigid@rhel7: RHEL-07-040400 + +ocil_clause: 'MACs option is commented out or not using FIPS-approved hash algorithms' + +ocil: |- + Only FIPS-approved MACs should be used. To verify that only FIPS-approved + MACs are in use, run the following command: + 
$ sudo grep -i macs /etc/ssh/sshd_config
+ The output should contain only following MACs (or a subset) in the exact order: + 
hmac-sha2-512,hmac-sha2-256
+ +warnings: + - general: |- + The system needs to be rebooted for these changes to take effect. + - regulatory: |- + System Crypto Modules must be provided by a vendor that undergoes + FIPS-140 certifications. + FIPS-140 is applicable to all Federal agencies that use + cryptographic-based security systems to protect sensitive information + in computer and telecommunication systems (including voice systems) as + defined in Section 5131 of the Information Technology Management Reform + Act of 1996, Public Law 104-106. This standard shall be used in + designing and implementing cryptographic modules that Federal + departments and agencies operate or are operated for them under + contract. See {{{ weblink(link="https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf") }}} + To meet this, the system has to have cryptographic software provided by + a vendor that has undergone this certification. This means providing + documentation, test results, design information, and independent third + party review by an accredited lab. While open source software is + capable of meeting this, it does not meet FIPS-140 unless the vendor + submits to this process. From 18ea3b8671e15c06a5c1c864d9d1d67f4262189e Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Tue, 19 Jan 2021 12:32:25 +0100 Subject: [PATCH 2/7] add tests --- .../tests/comment.fail.sh | 7 +++++++ .../tests/correct_reduced_list.pass.sh | 7 +++++++ .../tests/correct_scrambled.fail.sh | 7 +++++++ .../tests/correct_value.pass.sh | 7 +++++++ .../tests/line_not_there.fail.sh | 3 +++ .../tests/no_parameters.fail.sh | 7 +++++++ .../tests/wrong_value.fail.sh | 7 +++++++ 7 files changed, 45 insertions(+) create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/comment.fail.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_reduced_list.pass.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_scrambled.fail.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_value.pass.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/line_not_there.fail.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/no_parameters.fail.sh create mode 100644 linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/wrong_value.fail.sh diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/comment.fail.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/comment.fail.sh new file mode 100644 index 0000000000..26bf18234c --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/comment.fail.sh @@ -0,0 +1,7 @@ +#!/bin/bash + +if grep -q "^MACs" /etc/ssh/sshd_config; then + sed -i "s/^MACs.*/# MACs hmac-sha2-512,hmac-sha2-256/" /etc/ssh/sshd_config +else + echo "# ciphers MACs hmac-sha2-512,hmac-sha2-256" >> /etc/ssh/sshd_config +fi diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_reduced_list.pass.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_reduced_list.pass.sh new file mode 100644 index 0000000000..0d922cdee9 --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_reduced_list.pass.sh @@ -0,0 +1,7 @@ +#!/bin/bash + +if grep -q "^MACs" /etc/ssh/sshd_config; then + sed -i "s/^MACs.*/MACs hmac-sha2-512/" /etc/ssh/sshd_config +else + echo "MACs hmac-sha2-512" >> /etc/ssh/sshd_config +fi diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_scrambled.fail.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_scrambled.fail.sh new file mode 100644 index 0000000000..ce3f459352 --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_scrambled.fail.sh @@ -0,0 +1,7 @@ +#!/bin/bash + +if grep -q "^MACs" /etc/ssh/sshd_config; then + sed -i "s/^MACs.*/MACs hmac-sha2-256,hmac-sha2-512/" /etc/ssh/sshd_config +else + echo "MACs hmac-sha2-256,hmac-sha2-512" >> /etc/ssh/sshd_config +fi diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_value.pass.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_value.pass.sh new file mode 100644 index 0000000000..19da7102a7 --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/correct_value.pass.sh @@ -0,0 +1,7 @@ +#!/bin/bash + +if grep -q "^MACs" /etc/ssh/sshd_config; then + sed -i "s/^MACs.*/MACs hmac-sha2-512,hmac-sha2-256/" /etc/ssh/sshd_config +else + echo 'MACs hmac-sha2-512,hmac-sha2-256' >> /etc/ssh/sshd_config +fi diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/line_not_there.fail.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/line_not_there.fail.sh new file mode 100644 index 0000000000..fd1f19347a --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/line_not_there.fail.sh @@ -0,0 +1,3 @@ +#!/bin/bash + +sed -i "/^MACs.*/d" /etc/ssh/sshd_config diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/no_parameters.fail.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/no_parameters.fail.sh new file mode 100644 index 0000000000..44c07c6de0 --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/no_parameters.fail.sh @@ -0,0 +1,7 @@ +#!/bin/bash + +if grep -q "^MACs" /etc/ssh/sshd_config; then + sed -i "s/^MACs.*/MACs /" /etc/ssh/sshd_config +else + echo 'MACs ' >> /etc/ssh/sshd_config +fi diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/wrong_value.fail.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/wrong_value.fail.sh new file mode 100644 index 0000000000..cf56cd228f --- /dev/null +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/tests/wrong_value.fail.sh @@ -0,0 +1,7 @@ +#!/bin/bash + +if grep -q "^MACs" /etc/ssh/sshd_config; then + sed -i "s/^MACs.*/MACs hmac-sha2-512,hmac-sha2-256,blahblah/" /etc/ssh/sshd_config +else + echo "MACs hmac-sha2-512,hmac-sha2-256,blahblah" >> /etc/ssh/sshd_config +fi From a334b4b434adf92c94b8bd6bb888751782e70ad3 Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Tue, 19 Jan 2021 12:32:58 +0100 Subject: [PATCH 3/7] modify rhel7 stig profile --- rhel7/profiles/stig.profile | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/rhel7/profiles/stig.profile b/rhel7/profiles/stig.profile index 6c06a8ede6..17c781d3eb 100644 --- a/rhel7/profiles/stig.profile +++ b/rhel7/profiles/stig.profile @@ -28,7 +28,6 @@ selections: - inactivity_timeout_value=15_minutes - var_screensaver_lock_delay=5_seconds - sshd_idle_timeout_value=10_minutes - - sshd_approved_macs=stig - var_accounts_fail_delay=4 - var_selinux_state=enforcing - var_selinux_policy_name=targeted @@ -259,7 +258,7 @@ selections: - sshd_print_last_log - sshd_disable_root_login - sshd_allow_only_protocol2 - - sshd_use_approved_macs + - sshd_use_approved_macs_ordered_stig - file_permissions_sshd_pub_key - file_permissions_sshd_private_key - sshd_disable_gssapi_auth From df71fc735efa8754a73fab5d355d422c6e0ffa53 Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Tue, 19 Jan 2021 12:33:10 +0100 Subject: [PATCH 4/7] remove rhel7 stigid from sshd_use_approved_macs --- .../services/ssh/ssh_server/sshd_use_approved_macs/rule.yml | 1 - 1 file changed, 1 deletion(-) diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs/rule.yml b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs/rule.yml index 394c733f51..d47eb443f5 100644 --- a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs/rule.yml +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs/rule.yml @@ -54,7 +54,6 @@ references: nist-csf: PR.AC-1,PR.AC-3,PR.DS-5,PR.PT-4 srg: SRG-OS-000125-GPOS-00065,SRG-OS-000250-GPOS-00093,SRG-OS-000394-GPOS-00174 vmmsrg: SRG-OS-000033-VMM-000140,SRG-OS-000120-VMM-000600,SRG-OS-000478-VMM-001980,SRG-OS-000480-VMM-002000,SRG-OS-000396-VMM-001590 - stigid@rhel7: RHEL-07-040400 stigid@sle12: SLES-12-030180 isa-62443-2013: 'SR 1.1,SR 1.13,SR 1.2,SR 1.3,SR 1.4,SR 1.5,SR 1.7,SR 1.8,SR 1.9,SR 2.6,SR 3.1,SR 3.5,SR 3.8,SR 4.1,SR 4.3,SR 5.1,SR 5.2,SR 5.3,SR 7.1,SR 7.6' isa-62443-2009: 4.3.3.5.1,4.3.3.6.6 From 9c24aaaba67f0123a82335672fd25aacd913caa4 Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Thu, 21 Jan 2021 11:43:16 +0100 Subject: [PATCH 5/7] simplify regex --- .../sshd_use_approved_macs_ordered_stig/oval/shared.xml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml index d7fbd9f0ed..5973488661 100644 --- a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml @@ -31,7 +31,7 @@ /etc/ssh/sshd_config - ^[\s]*(?i)MACs(?-i)[\s]+(?=[\w,-@]+)(hmac-sha2-512(?=[\w,-@]+|$),?)?(hmac-sha2-256(?=[\w,-@]+|$),?)?[\s]*(?:#.*)?$ + ^[\s]*(?i)MACs(?-i)[\s]+(?=[\w,-@]+)(hmac-sha2-512(?=[\w,]+|$),?)?(hmac-sha2-256)?[\s]*(?:#.*)?$ 1 From e3973f4c2988308a2d1a18e67a730a059f791336 Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Thu, 21 Jan 2021 11:55:19 +0100 Subject: [PATCH 6/7] make bash remediation more readable --- .../sshd_use_approved_macs_ordered_stig/bash/shared.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh index c76190fb96..f8f6f39bee 100644 --- a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/bash/shared.sh @@ -1,6 +1,6 @@ # platform = multi_platform_wrlinux,Red Hat Enterprise Linux 7,Oracle Linux 7 -if grep -q -P '^[[:space:]]*MACs[[:space:]]+' /etc/ssh/sshd_config; then +if grep -q -P '^\s*MACs\s+' /etc/ssh/sshd_config; then sed -i 's/^\s*MACs.*/MACs hmac-sha2-512,hmac-sha2-256/' /etc/ssh/sshd_config else echo "MACs hmac-sha2-512,hmac-sha2-256" >> /etc/ssh/sshd_config From e5c379ac8cbd7bd42b116d3a5473a78406a662fd Mon Sep 17 00:00:00 2001 From: Vojtech Polasek Date: Thu, 21 Jan 2021 13:05:18 +0100 Subject: [PATCH 7/7] one more small fix to oval regex --- .../sshd_use_approved_macs_ordered_stig/oval/shared.xml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml index 5973488661..b5443b07c4 100644 --- a/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml +++ b/linux_os/guide/services/ssh/ssh_server/sshd_use_approved_macs_ordered_stig/oval/shared.xml @@ -31,7 +31,7 @@ /etc/ssh/sshd_config - ^[\s]*(?i)MACs(?-i)[\s]+(?=[\w,-@]+)(hmac-sha2-512(?=[\w,]+|$),?)?(hmac-sha2-256)?[\s]*(?:#.*)?$ + ^[\s]*(?i)MACs(?-i)[\s]+(?=[\w]+)(hmac-sha2-512(?=[\w,]+|$),?)?(hmac-sha2-256)?[\s]*(?:#.*)?$ 1