Technical | May 17, 2023 20 min to read

Securing Veeam Hardened Repository

After selecting the right hardware for the Veeam Backup & Replication Hardened Repository and installing the Ubuntu Linux operating system, the next step is secure the operating system according to the DISA STIG (Defense Information Systems Agency Security Technical Implementation Guides) guidelines.

This blog post describes the hardening process for Ubuntu 20.04 free edition. For Ubuntu Pro users, there is an easier way. To keep it as simple as possible, Veeam provides a script that automates the setting of security options. The requirement for the script to work is such that Ubuntu is set up as described in the installing the Ubuntu Linux blog post.

Prerequisites

Before starting the hardening process, let’s recap the current state and adjust settings if needed.

Hardware monitoring is enabled in the out-of-band management of the Hardened Repository server. Vendor-specific hardware monitoring tools are not covered in this blog post
Minimal Ubuntu installation on an UEFI Secure boot-enabled physical system (virtual machines are unsupported/only for test installations)
There is only one user account with full sudo permissions, and the root account is locked (no password)
UDP port 123 outgoing is open on the firewall to the following servers (servers can be changed if needed. More details on NTP are available in this blog post and will be covered later in this article)
- tick.usno.navy.mil
- tock.usno.navy.mil
- ntp2.usno.navy.mil

That’s it! Let’s start securing Veeam Hardened Repository.

Getting started

After installing Ubuntu as described in this blog post, there are two ways to connect or manage the Veeam Hardened Repository.

Direct login via the console (usually via a remote management console web interface)
SSH (secure shell)

The easiest way is using SSH, because it supports copy and paste. One popular SSH client is Putty, which is included in the Veeam Backup & Replication installation.

wget https://vee.am/harddisa

Before running the script, it’s recommended that you understand what it does and what it does not do. The script applies DISA STIG security settings where applicable. That means the script implements things like password policies, audit rules, permissions or TCP security settings. The STIGs also have requirements for systems with graphical user interface or user management via a directory service. As the Hardened Repository is a “minimal installation” standalone machine, things like that don’t apply and are “not applicable”. A full list of settings is available in the Appendix.

This guide assumes that customers reading this guide are new to Linux or have only basic Linux knowledge. The hardening script skips settings that have notifications where someone should do something manually on the Hardened Repository server as root. That is because the final and manual hardening step after the Veeam hardening script will remove root and sudo permissions and disable SSH remote management. This is a hard step, but it addresses concerns around “I can log in as root and delete files.”

Note:

Only Veeam Backup & Replication v12 and later is compatible with DISA STIG hardening. If you are using earlier versions, please upgrade to V12 first.

For advanced Linux users: Feel free to use the script to save time. If you are using automation with Ansible, there is material available for that as well.

Apply DISA STIG Requirements

You can also apply each hardening step of the DISA STIGs manually. On the DISA document library, search for Ubuntu, download the guidelines and open them with DISA STIG Viewer. Most rules have a code example to apply the guideline.

The script in this article handles the rules of the guidelines to make your life easier. Before running the hardening script, one needs to make sure that NTP traffic is allowed to the servers listed in the script (tick.usno.navy.mil, tock.usno.navy.mil and ntp2.usno.navy.mil). Alternatively, one can change the script to other time sources, or configure time manually and delete the time configuration section in the script. Apply the guidelines by running the script with the following command:

sudo bash harddisa

The output will look like this. Explanations on all the steps are provided later in this document.

After the hardening script finished, the Veeam Hardened Repository role can be installed.

Install Hardened Repository Role

Technically, installing the Hardened Repository role could also be done before doing the hardening. Before adding the Hardened Repository role, you need to configure the filesystem path where the backup data will be stored in future. In the “Installing Ubuntu Linux for Veeam Hardened Repository” blog, we defined /mnt/backup as the path for backup data storage. This path needs to be owned by the Hardened Repository user and we will limit permissions only to that user (veeamrepo in our case):

sudo chown –R veeamrepo:veeamrepo /mnt/backup
sudo chmod 700 /mnt/backup

The user guide describes how to install the Veeam Hardened Repository role. Please note that the ‘use “su” if “sudo” fails’ option cannot be used because the root account has no password/is locked.

After installation of the Hardened Repository, there is still one user with full “sudo” privileges. Let’s close this.

Locking It Down

There are a few steps where we decided to keep it a manual process instead of automating it with the hardening script. One of them (others are described in the appendix table) is UBTU-20-010009, which states: “Ubuntu operating systems when booted must require authentication upon booting into single-user and maintenance modes.”Single-user mode is a way to get into the system after locking down Hardened Repository as described in the next section.

Protecting single-user mode against unauthorized access is described in a separate blog post.

These following steps are outside the official DISA STIG hardening guides. These steps are the answer to customer concerns about the security of Hardened Repository and the criticism that one can “simply” log in as root and delete everything.

Note:

Only do the following steps after installing the Hardened Repository role. You will no longer have root/administrative access to the machine after executing the following steps. If you have locked yourself out accidentally, please refer to the “Ubuntu Linux essentials: Booting into single user mode and protecting against unauthorized access” blog post.

First, we will disable SSH remote management. The following command disables the SSH service, so that it does not start automatically during boot time.

sudo systemctl disable ssh

You can continue working with SSH until the next reboot. You can also stop the SSH service directly and the current SSH session will continue to work. But you can no longer reconnect after stopping the SSH service. The following command stops the SSH service:

sudo systemctl stop ssh

The last commands above used “sudo” to give you root permissions. Root permissions are no longer needed to run Veeam Hardened Repository. We will only allow two commands: reboot and shutdown.

The overall concept of the following steps is also described in the Installing Ubuntu Linux for Veeam Hardened Repository blog post.

Replace the username with the username “veeamrepo” you are currently using:

sudo bash -c "echo 'veeamrepo ALL = (root) NOEXEC: /usr/sbin/reboot' >> /etc/sudoers"
sudo bash -c "echo 'veeamrepo ALL = (root) NOEXEC: /usr/sbin/shutdown' >> /etc/sudoers"

Now remove yourself from the sudo group. After executing the command below and next login, you lose your sudo permissions. To get full root/sudo permissions again, you must boot into “single-user mode”. Run this command only as last step!

sudo deluser veeamrepo sudo

With that, the configuration of the Hardened Repository itself is finished. But there are some more settings to become compliant with DISA STIGs.

Required Configurations on the Veeam Backup & Replication Side

There are DISA STIG requirements around encryption (see table below) that can be configured on the Hardened Repository directly or in Veeam Backup & Replication. The operating system data itself does not require protection. Only the backup data needs to be protected. One can protect the backup data also via disk encryption, but that increases complexity. It’s easier to manage encryption on the Veeam Backup & Replication side in the job settings.

STIG ID	Severity	Rule title	Explanation
UBTU-20-010414	medium	Ubuntu operating systems handling data requiring “data at rest” protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest.	Configure health checks and encryption in the job settings. Disk encryption could be used alternatively.
UBTU-20-010444	medium	Ubuntu operating system must implement cryptographic mechanisms to prevent unauthorized modification of all information at rest.	Configure health checks in the job settings. Disk encryption could be used alternatively.
UBTU-20-010445	medium	Ubuntu operating system must implement cryptographic mechanisms to prevent unauthorized disclosure of all information at rest.	Configure encryption in the job settings. Disk encryption could be used alternatively.

Summary

As a “software only” vendor, Veeam offers customers flexibility regarding which hardware or operating system to use. On the other hand, customers ask for security best practices. Note the following blog series:

Selecting Hardware and Setting Up Environment for Veeam Hardened Repository
Installing Ubuntu Linux for Veeam Hardened Repository
Securing Veeam Hardened Repository (this blog post)

With this blog series, customers are prepared to achieve trusted immutability by applying globally recognized DISA STIG cybersecurity standards on top of Veeam best practices. If you are looking for pre-configured immutable hardware, where you don’t need to manage the hardware and operating system yourself, then there are several options:

Object storage with immutability support. There are around 30 partner solutions available today.
As secondary target (remember the 3-2-1 Rule) you can use the HPE StoreOnce deduplication appliance with immutability.
If tape is an option, then WORM tape media can ensure that data can never be deleted again (while with immutability, data can be deleted after the immutability retention is over).
“Veeam Hardened Repository” as a service is offered by regional service providers (availability varies depending on location).

Appendix

The table below shows DISA STIG requirements that must be applied manually on the server hardware or in Veeam Backup & Replication.

STIG ID	Severity	Rule title	Comment
UBTU-20-010009	high	Ubuntu operating systems when booted must require authentication upon booting into single-user and maintenance modes.	Described above
UBTU-20-010012	high	The Ubuntu operating system must ensure only users who need access to security functions are part of sudo group.	Described above
UBTU-20-010414	medium	Ubuntu operating systems handling data requiring “data at rest” protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest.	Described above
UBTU-20-010444	medium	Ubuntu operating system must implement cryptographic mechanisms to prevent unauthorized modification of all information at rest.	Described above
UBTU-20-010445	medium	Ubuntu operating system must implement cryptographic mechanisms to prevent unauthorized disclosure of all information at rest.	Described above
UBTU-20-010447	medium	The Ubuntu operating system must implement non-executable data to protect its memory from unauthorized code execution.	BIOS/UEFI setting
UBTU-20-010455	medium	The Ubuntu operating system must disable all wireless network adapters.	Ensure that no wireless network adapters are used

The table below shows the DISA STIG requirements that were implemented automatically by the script or are default settings.

STIG ID	Severity	Rule Title	Comment
UBTU-20-010005	medium	The Ubuntu operating system must allow users to directly initiate a session lock for all connection types.
UBTU-20-010007	low	The Ubuntu operating system must enforce 24 hours/1 day as the minimum password lifetime. Passwords for new users must have a 24 hours/1 day minimum password lifetime restriction.
UBTU-20-010008	low	The Ubuntu operating system must enforce a 60-day maximum password lifetime restriction. Passwords for new users must have a 60-day maximum password lifetime restriction.
UBTU-20-010013	medium	The Ubuntu operating system must automatically terminate a user session after inactivity timeouts have expired.
UBTU-20-010014	medium	The Ubuntu operating system must require users to reauthenticate for privilege escalation or when changing roles.
UBTU-20-010016	medium	The Ubuntu operating system default filesystem permissions must be defined in such a way that all authenticated users can read and modify only their own files.
UBTU-20-010035	medium	The Ubuntu operating system must use strong authenticators in establishing nonlocal maintenance and diagnostic sessions.
UBTU-20-010036	medium	The Ubuntu operating system must immediately terminate all network connections associated with SSH traffic after a period of inactivity.
UBTU-20-010037	medium	The Ubuntu operating system must immediately terminate all network connections associated with SSH traffic at the end of the session or after 10 minutes of inactivity.
UBTU-20-010038	medium	The Ubuntu operating system must display the Standard Mandatory DoD Notice and Consent Banner before granting any local or remote connection to the system.	Generic banner is used instead of DoD Notice.
UBTU-20-010042	high	The Ubuntu operating system must use SSH to protect the confidentiality and integrity of transmitted information.
UBTU-20-010043	medium	The Ubuntu operating system must configure the SSH daemon to use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hashes to prevent the unauthorized disclosure of information and/or detect changes to information during transmission.
UBTU-20-010047	high	The Ubuntu operating system must not allow unattended or automatic login via SSH.
UBTU-20-010048	high	The Ubuntu operating system must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements.
UBTU-20-010049	medium	The Ubuntu operating system SSH daemon must prevent remote hosts from connecting to the proxy display.
UBTU-20-010050	low	The Ubuntu operating system must enforce password complexity by requiring that at least one upper-case character be used.
UBTU-20-010051	low	The Ubuntu operating system must enforce password complexity by requiring that at least one lower-case character be used.
UBTU-20-010052	low	The Ubuntu operating system must enforce password complexity by requiring that at least one numeric character be used.
UBTU-20-010053	low	The Ubuntu operating system must require the change of at least 8 characters when passwords are changed.
UBTU-20-010054	medium	The Ubuntu operating system must enforce a minimum 15-character password length.
UBTU-20-010055	low	The Ubuntu operating system must enforce password complexity by requiring that at least one special character be used.
UBTU-20-010056	medium	The Ubuntu operating system must prevent the use of dictionary words for passwords.
UBTU-20-010057	medium	The Ubuntu operating system must be configured so that when passwords are changed or new passwords are established, pwquality must be used.
UBTU-20-010070	low	The Ubuntu operating system must prohibit password reuse for a minimum of five generations.
UBTU-20-010072	low	The Ubuntu operating system must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts have been made.
UBTU-20-010074	medium	The Ubuntu operating system must be configured so that the script which runs each 30 days or less to check file integrity is the default one.
UBTU-20-010075	low	The Ubuntu operating system must enforce a delay of at least 4 seconds between logon prompts following a failed logon attempt.
UBTU-20-010100	medium	The Ubuntu operating system must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/passwd.
UBTU-20-010101	medium	The Ubuntu operating system must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/group.
UBTU-20-010102	medium	The Ubuntu operating system must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/shadow.
UBTU-20-010103	medium	The Ubuntu operating system must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/gshadow.
UBTU-20-010104	medium	The Ubuntu operating system must generate audit records for all account creations, modifications, disabling, and termination events that affect /etc/opasswd.
UBTU-20-010118	medium	The Ubuntu operating system must shut down by default upon audit failure (unless availability is an overriding concern).
UBTU-20-010122	medium	The Ubuntu operating system must be configured so that audit log files are not read or write-accessible by unauthorized users.
UBTU-20-010123	medium	The Ubuntu operating system must be configured to permit only authorized users ownership of the audit log files.
UBTU-20-010124	medium	The Ubuntu operating system must permit only authorized groups ownership of the audit log files.
UBTU-20-010128	medium	The Ubuntu operating system must be configured so that the audit log directory is not write-accessible by unauthorized users.
UBTU-20-010133	medium	The Ubuntu operating system must be configured so that audit configuration files are not write-accessible by unauthorized users.
UBTU-20-010134	medium	The Ubuntu operating system must permit only authorized accounts to own the audit configuration files.
UBTU-20-010135	medium	The Ubuntu operating system must permit only authorized groups to own the audit configuration files.
UBTU-20-010136	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the su command.
UBTU-20-010137	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chfn command.
UBTU-20-010138	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the mount command.
UBTU-20-010139	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the umount command.
UBTU-20-010140	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the ssh-agent command.
UBTU-20-010141	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the ssh-keysign command.
UBTU-20-010142	medium	The Ubuntu operating system must generate audit records for any use of the setxattr, fsetxattr, lsetxattr, removexattr, fremovexattr, and lremovexattr system calls.
UBTU-20-010148	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chown, fchown, fchownat, and lchown system calls.
UBTU-20-010152	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chmod, fchmod, and fchmodat system calls.
UBTU-20-010155	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the creat, open, openat, open_by_handle_at, truncate, and ftruncate system calls.
UBTU-20-010161	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the sudo command.
UBTU-20-010162	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the sudoedit command.
UBTU-20-010163	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chsh command.
UBTU-20-010164	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the newgrp command.
UBTU-20-010165	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chcon command.
UBTU-20-010166	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the apparmor_parser command.
UBTU-20-010167	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the setfacl command.
UBTU-20-010168	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chacl command.
UBTU-20-010169	medium	The Ubuntu operating system must generate audit records for the use and modification of the tallylog file.
UBTU-20-010170	medium	The Ubuntu operating system must generate audit records for the use and modification of faillog file.
UBTU-20-010171	medium	The Ubuntu operating system must generate audit records for the use and modification of the lastlog file.
UBTU-20-010172	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the passwd command.
UBTU-20-010173	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the unix_update command.
UBTU-20-010174	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the gpasswd command.
UBTU-20-010175	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the chage command.
UBTU-20-010176	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the usermod command.
UBTU-20-010177	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the crontab command.
UBTU-20-010178	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the pam_timestamp_check command.
UBTU-20-010179	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the init_module and finit_module syscalls.
UBTU-20-010181	medium	The Ubuntu operating system must generate audit records for successful/unsuccessful uses of the delete_module syscall.
UBTU-20-010182	medium	The Ubuntu operating system must produce audit records and reports containing information to establish when, where, what type, the source, and the outcome for all DoD-defined auditable events and actions in near real time.
UBTU-20-010198	medium	The Ubuntu operating system must initiate session audits at system start-up.
UBTU-20-010199	medium	The Ubuntu operating system must configure audit tools with a mode of 0755 or less permissive.
UBTU-20-010200	medium	The Ubuntu operating system must configure audit tools to be owned by root.
UBTU-20-010201	medium	The Ubuntu operating system must configure the audit tools to be group-owned by root.
UBTU-20-010205	medium	The Ubuntu operating system must use cryptographic mechanisms to protect the integrity of audit tools.
UBTU-20-010211	medium	The Ubuntu operating system must prevent all software from executing at higher privilege levels than users executing the software and the audit system must be configured to audit the execution of privileged functions.
UBTU-20-010230	low	The Ubuntu operating system must record time stamps for audit records that can be mapped to Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT).
UBTU-20-010244	medium	The Ubuntu operating system must generate audit records for privileged activities, nonlocal maintenance, diagnostic sessions and other system-level access.
UBTU-20-010267	medium	The Ubuntu operating system must generate audit records for any successful/unsuccessful use of unlink, unlinkat, rename, renameat, and rmdir system calls.
UBTU-20-010277	medium	The Ubuntu operating system must generate audit records for the /var/log/wtmp file.
UBTU-20-010278	medium	The Ubuntu operating system must generate audit records for the /var/run/wtmp file.
UBTU-20-010279	medium	The Ubuntu operating system must generate audit records for the /var/log/btmp file.
UBTU-20-010296	medium	The Ubuntu operating system must generate audit records when successful/unsuccessful attempts to use modprobe command.
UBTU-20-010297	medium	The Ubuntu operating system must generate audit records when successful/unsuccessful attempts to use the kmod command.
UBTU-20-010298	medium	The Ubuntu operating system must generate audit records when successful/unsuccessful attempts to use the fdisk command.
UBTU-20-010400	low	The Ubuntu operating system must limit the number of concurrent sessions to ten for all accounts and/or account types.
UBTU-20-010403	medium	The Ubuntu operating system must monitor remote access methods.
UBTU-20-010404	medium	The Ubuntu operating system must encrypt all stored passwords with a FIPS 140-2 approved cryptographic hashing algorithm.
UBTU-20-010405	high	The Ubuntu operating system must not have the telnet package installed.
UBTU-20-010406	high	The Ubuntu operating system must not have the rsh-server package installed.
UBTU-20-010407	medium	The Ubuntu operating system must be configured to prohibit or restrict the use of functions, ports, protocols, and/or services, as defined in the PPSM CAL and vulnerability assessments.
UBTU-20-010408	medium	The Ubuntu operating system must prevent direct login into the root account.
UBTU-20-010411	medium	The Ubuntu operating system must set a sticky bit on all public directories to prevent unauthorized and unintended information transferred via shared system resources.
UBTU-20-010412	medium	The Ubuntu operating system must be configured to use TCP syncookies.
UBTU-20-010413	medium	The Ubuntu operating system must disable kernel core dumps so that it can fail to a secure state if system initialization fails, shutdown fails or aborts fail.
UBTU-20-010416	medium	The Ubuntu operating system must generate error messages that provide information necessary for corrective actions without revealing information that could be exploited by adversaries.
UBTU-20-010417	medium	The Ubuntu operating system must configure the /var/log directory to be group-owned by syslog.
UBTU-20-010418	medium	The Ubuntu operating system must configure the /var/log directory to be owned by root.
UBTU-20-010419	medium	The Ubuntu operating system must configure the /var/log directory to have mode 0750 or less permissive.
UBTU-20-010420	medium	The Ubuntu operating system must configure the /var/log/syslog file to be group-owned by adm.	Logs of processes running with reduced permissions are in /tmp/VeeamBackup because of this
UBTU-20-010421	medium	The Ubuntu operating system must configure /var/log/syslog file to be owned by syslog.
UBTU-20-010422	medium	The Ubuntu operating system must configure /var/log/syslog file with mode 0640 or less permissive.
UBTU-20-010423	medium	The Ubuntu operating system must have directories that contain system commands set to a mode of 0755 or less permissive.
UBTU-20-010424	medium	The Ubuntu operating system must have directories that contain system commands owned by root.
UBTU-20-010425	medium	The Ubuntu operating system must have directories that contain system commands group-owned by root.
UBTU-20-010426	medium	The Ubuntu operating system library files must have mode 0755 or less permissive.
UBTU-20-010427	medium	The Ubuntu operating system library directories must have mode 0755 or less permissive.
UBTU-20-010428	medium	The Ubuntu operating system library files must be owned by root.
UBTU-20-010429	medium	The Ubuntu operating system library directories must be owned by root.
UBTU-20-010430	medium	The Ubuntu operating system library files must be group-owned by root or a system account.
UBTU-20-010431	medium	The Ubuntu operating system library directories must be group-owned by root.
UBTU-20-010432	medium	The Ubuntu operating system must be configured to preserve log records from failure events.
UBTU-20-010433	medium	The Ubuntu operating system must have an application firewall installed in order to control remote access methods.
UBTU-20-010434	medium	The Ubuntu operating system must enable and run the uncomplicated firewall(ufw).
UBTU-20-010435	medium	The Ubuntu operating system must, for networked systems, compare internal information system clocks at least every 24 hours with a server which is synchronized to one of the redundant United States Naval Observatory (USNO) time servers, or a time server designated for the appropriate DoD network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS).	The script sets the “-R” flag in /etc/defaults/chrony That prevents chrony from making big time changes during boot or restart of the service. See this blog post for details.
UBTU-20-010438	medium	The Ubuntu operating system’s Advance Package Tool (APT) must be configured to prevent the installation of patches, service packs, device drivers, or Ubuntu operating system components without verification they have been digitally signed using a certificate that is recognized and approved by the organization.
UBTU-20-010439	medium	The Ubuntu operating system must be configured to use AppArmor.
UBTU-20-010446	medium	The Ubuntu operating system must configure the uncomplicated firewall to rate-limit impacted network interfaces.
UBTU-20-010448	medium	The Ubuntu operating system must implement address space layout randomization to protect its memory from unauthorized code execution.
UBTU-20-010449	medium	The Ubuntu operating system must be configured so that Advance Package Tool (APT) removes all software components after updated versions have been installed.
UBTU-20-010450	medium	The Ubuntu operating system must use a file integrity tool to verify correct operation of all security functions.
UBTU-20-010451	medium	The Ubuntu operating system must notify designated personnel if baseline configurations are changed in an unauthorized manner. The file integrity tool must notify the System Administrator when changes to the baseline configuration or anomalies in the operation of any security functions are discovered.
UBTU-20-010453	low	The Ubuntu operating system must display the date and time of the last successful account logon upon logon.
UBTU-20-010454	medium	The Ubuntu operating system must have an application firewall enabled.
UBTU-20-010456	medium	The Ubuntu operating system must have system commands set to a mode of 0755 or less permissive.
UBTU-20-010457	medium	The Ubuntu operating system must have system commands owned by root or a system account.
UBTU-20-010458	medium	The Ubuntu operating system must have system commands group-owned by root or a system account.
UBTU-20-010460	high	The Ubuntu operating system must disable the x86 Ctrl-Alt-Delete key sequence.
UBTU-20-010462	high	The Ubuntu operating system must not have accounts configured with blank or null passwords.
UBTU-20-010463	high	The Ubuntu operating system must not allow accounts configured with blank or null passwords.
UBTU-20-010461	medium	The Ubuntu operating system must disable automatic mounting of Universal Serial Bus (USB) mass storage driver.

The table below shows the DISA STIG requirements that are not applicable. Many of them are out of scope because there is only one (locked down) user account, no graphical user interface and this guide does not require having a mail server set up for notifications. FIPS compliance can also only be achieved by using Ubuntu Pro, while this guide refers to the free version.

STIG ID	Severity	Rule Title	Comment
UBTU-20-010000	medium	The Ubuntu operating system must provision temporary user accounts with an expiration time of 72 hours or less.	There are no temporary accounts.
UBTU-20-010002	medium	The Ubuntu operating system must enable the graphical user logon banner to display the Standard Mandatory DoD Notice and Consent Banner before granting local access to the system via a graphical user logon.	No GUI installed
UBTU-20-010003	medium	The Ubuntu operating system must display the Standard Mandatory DoD Notice and Consent Banner before granting local access to the system via a graphical user logon.	No GUI installed
UBTU-20-010004	medium	The Ubuntu operating system must retain a user’s session lock until that user re-establishes access using established identification and authentication procedures.	No GUI installed
UBTU-20-010006	high	The Ubuntu operating system must map the authenticated identity to the user or group account for PKI-based authentication.	Only one (locked down) user on the system.
UBTU-20-010010	medium	The Ubuntu operating system must uniquely identify interactive users.	There are no interactive users
UBTU-20-010033	medium	The Ubuntu operating system must implement smart card logins for multifactor authentication for local and network access to privileged and non-privileged accounts.	There are no interactive users
UBTU-20-010044	medium	The Ubuntu operating system must configure the SSH daemon to use FIPS 140-2 approved ciphers to prevent the unauthorized disclosure of information and/or detect changes to information during transmission.	SSH is disabled
UBTU-20-010060	medium	The Ubuntu operating system, for PKI-based authentication, must validate certificates by constructing a certification path (which includes status information) to an accepted trust anchor.	There are no interactive users
UBTU-20-010063	medium	The Ubuntu operating system must implement multifactor authentication for remote access to privileged accounts in such a way that one of the factors is provided by a device separate from the system gaining access.	There is no remote access to privileged accounts
UBTU-20-010064	medium	The Ubuntu operating system must accept Personal Identity Verification (PIV) credentials.	There are no interactive users and no smart cards
UBTU-20-010065	medium	The Ubuntu operating system must electronically verify Personal Identity Verification (PIV) credentials.	There are no interactive users and no smart cards
UBTU-20-010066	medium	The Ubuntu operating system for PKI-based authentication, must implement a local cache of revocation data in case of the inability to access revocation information via the network.	There are no interactive users and no smart cards
UBTU-20-010117	medium	The Ubuntu operating system must alert the ISSO and SA (at a minimum) in the event of an audit processing failure.	This guide does not require 3^rd party services for notifications
UBTU-20-010215	low	The Ubuntu operating system must allocate audit record storage capacity to store at least one weeks’ worth of audit records, when audit records are not immediately sent to a central audit record storage facility.	Setting up configuration for audit storage 5GB are for /var/log/audit – as there should be almost nothing in the logs, this should be more than enough We just use percentage value, we don’t have knowledge about customer audit volume.
UBTU-20-010216	low	The Ubuntu operating system audit event multiplexor must be configured to off-load audit logs onto a different system or storage media from the system being audited.	This guide does not require 3^rd party services for notifications
UBTU-20-010217	low	The Ubuntu operating system must immediately notify the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75% of the repository maximum audit record storage capacity.	This guide does not require 3^rd party services for notifications
UBTU-20-010300	low	The Ubuntu operating system must have a crontab script running weekly to offload audit events of standalone systems.	This guide does not require 3^rd party services for notifications
UBTU-20-010409	medium	The Ubuntu operating system must disable account identifiers (individuals, groups, roles, and devices) after 35 days of inactivity.	There is only one (locked down) account
UBTU-20-010410	low	The Ubuntu operating system must automatically remove or disable emergency accounts after 72 hours.	There is only one (locked down) account
UBTU-20-010415	low	The Ubuntu operating system must deploy Endpoint Security for Linux Threat Prevention (ENSLTP).	This guide does not require 3^rd party products
UBTU-20-010436	low	The Ubuntu operating system must synchronize internal information system clocks to the authoritative time source when the time difference is greater than one second.	See UBTU-20-010435. The assumption is, that an attacker could manipulate the NTP servers or network communication
UBTU-20-010437	medium	The Ubuntu operating system must notify designated personnel if baseline configurations are changed in an unauthorized manner. The file integrity tool must notify the System Administrator when changes to the baseline configuration or anomalies in the oper	Default system settings We have no mail server configured
UBTU-20-010440	medium	The Ubuntu operating system must allow the use of a temporary password for system logons with an immediate change to a permanent password.	There is only one (locked down) account
UBTU-20-010441	low	The Ubuntu operating system must be configured such that Pluggable Authentication Module (PAM) prohibits the use of cached authentications after one day.	There are no cached credentials
UBTU-20-010442	high	The Ubuntu operating system must implement NIST FIPS-validated cryptography to protect classified information and for the following: to provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards.	Only Ubuntu Pro has that
UBTU-20-010443	medium	The Ubuntu operating system must only allow the use of DoD PKI-established certificate authorities for verification of the establishment of protected sessions.	There is only one (locked down) account
UBTU-20-010459	high	The Ubuntu operating system must disable the x86 Ctrl-Alt-Delete key sequence if a graphical user interface is installed.	No GUI installed.

Hannes Kasparick
Hannes Kasparick has been working in the IT business since 2004. He managed Windows, Linux, storage systems, firewalls and did consulting for data center solutions. Today Hannes is a member of the Veeam product management team.

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Table of Contents

Prerequisites
Getting started
Apply DISA STIG Requirements
Install Hardened Repository Role
Locking It Down
Required Configurations on the Veeam Backup & Replication Side
Summary
Appendix