What changed in Canonical Ubuntu 20.04 LTS SCAP Benchmark V2R5V2R5 changes

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AND - /boot/grub/grub.cfg uses password_pbkdf2 for root textfilecontent54_test (check: all, existence: all_exist) object textfilecontent54_object: filepath equals "/boot/grub/grub.cfg"; pattern pattern match "^\\s*(password\\S*)\\s+root\\s+"; instance greater than or equal "1" state textfilecontent54_state: subexpression equals "password_pbkdf2" Run the following command to verify the encrypted password is set: $ sudo grep -i password /boot/grub/grub.cfg password_pbkdf2 root grub.pbkdf2.sha512.10000.MFU48934NJA87HF8NSD34493GDHF84NG If the root password entry does not begin with "password_pbkdf2", this is a finding.

V-238204 in V2R5

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AND - /etc/ssh/sshd_config:MACs == FIPS-approved message authentication codes textfilecontent54_test (check: all, existence: at_least_one_exists) object textfilecontent54_object: filepath equals "/etc/ssh/sshd_config"; pattern pattern match "^\\s*(?i)MACs(?-i)[ \\t]+\\\"?([\\w,-]+)\\\"?[\\s]*(?:|(?:#.*))?$"; instance greater than or equal "1" state textfilecontent54_state: subexpression pattern match "^(hmac-sha2-512)|(hmac-sha2-512,hmac-sha2-256)|(hmac-sha2-256)$" Verify the SSH daemon is configured to only use MACs that employ FIPS 140-2 approved ciphers with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*macs' MACs hmac-sha2-512,hmac-sha2-256 If any ciphers other than "hmac-sha2-512" or "hmac-sha2-256" are listed, the order differs from the example above, or the returned line is commented out, this is a finding. If conflicting results are returned, this is a finding.

V-238216 in V2R5

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AND - /etc/ssh/sshd_config:Ciphers == DoD-approved ciphers textfilecontent54_test (check: all, existence: at_least_one_exists) object textfilecontent54_object: filepath equals "/etc/ssh/sshd_config"; pattern pattern match "^\\s*(?i)Ciphers(?-i)[ \\t]+\\\"?([\\w,-]+)\\\"?[\\s]*(?:|(?:#.*))?$"; instance greater than or equal "1" state textfilecontent54_state: subexpression pattern match "^(?:(aes256-ctr,aes192-ctr,aes128-ctr)|(aes256-ctr,aes192-ctr)|(aes256-ctr,aes128-ctr)|(aes192-ctr,aes128-ctr)|(aes256-ctr)|(aes192-ctr)|(aes128-ctr))$" Verify the SSH daemon is configured to only implement FIPS-approved algorithms by running the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ciphers' Ciphers aes256-ctr,aes192-ctr,aes128-ctr If any ciphers other than "aes256-ctr", "aes192-ctr", or "aes128-ctr" are listed, the order differs from the example above, the "Ciphers" keyword is missing, or the returned line is commented out, this is a finding. If conflicting results are returned, this is a finding.

V-238217 in V2R5

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AND - All files in /var/log except /var/log/btmp, /var/log/lastlog, and /var/log/wtmp are mode 640 or less permissive file_test (check: all, existence: any_exist) object file_object: filter equals "oval:mil.disa.stig.ubuntu2004unix:ste:2090323833705"; path equals "/var/log"; filename pattern match ".*"; behaviors equals "" state file_state: gexec equals "false"; oread equals "false"; uexec equals "false"; sticky equals "false"; sgid equals "false"; suid equals "false"; oexec equals "false"; owrite equals "false"; gwrite equals "false" Verify the Ubuntu operating system has all system log files under the "/var/log" directory with a permission set to "640" or less permissive by using the following command: Note: The btmp, wtmp, and lastlog files are excluded. Refer to the Discussion for details. $ sudo find /var/log -perm /137 ! -name '*[bw]tmp' ! -name '*lastlog' -type f -exec stat -c "%n %a" {} \; If the command displays any output, this is a finding. Note: If output regarding history.log or eipp.log.xz is displayed, this is not a finding.

Discussion

Any operating system providing too much information in error messages risks compromising the data and security of the structure, and contentorganizations ofmust error messages needs to be carefully consideredconsider by the organization.content and Organizations carefully consider the structure/content of error messages. The extent to which information systems are able to identify and handle error conditions is guided by organizational policy and operational requirements. Information that could be exploited by adversaries includes, for example, erroneous logon attempts with passwords entered by mistake as the username, mission/business information that can be derived from (if not stated explicitly by) information recorded, and personal information, such as account numbers, socialSocial securitySecurity numbers, and credit card numbers. The /var/log/btmp, /var/log/wtmp, and /var/log/lastlog files have group write and global read permissions to allow for the lastlog function to perform. Limiting the permissions beyond this configuration will result in the failure of functions that rely on the lastlog database.

V-238337 in V2R5