ANSSI-BP-028 (high)
Rules and Groups employed by this XCCDF Profile
-
File Permissions and Masks
Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which t...Group -
Verify Permissions on Important Files and Directories
Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses impo...Group -
Ensure All World-Writable Directories Are Owned by root User
All directories in local partitions which are world-writable should be owned by root. If any world-writable directories are not owned by root, this...Rule Medium Severity -
Verify that All World-Writable Directories Have Sticky Bits Set
When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky b...Rule Medium Severity -
Ensure All SGID Executables Are Authorized
The SGID (set group id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthoriz...Rule Medium Severity -
Ensure All SUID Executables Are Authorized
The SUID (set user id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthorize...Rule Medium Severity -
Ensure No World-Writable Files Exist
It is generally a good idea to remove global (other) write access to a file when it is discovered. However, check with documentation for specific a...Rule Medium Severity -
Ensure All Files Are Owned by a Group
If any file is not group-owned by a group present in /etc/group, the cause of the lack of group-ownership must be investigated. Following this, tho...Rule Medium Severity -
Ensure All Files Are Owned by a User
If any files are not owned by a user, then the cause of their lack of ownership should be investigated. Following this, the files should be deleted...Rule Medium Severity -
Enable Kernel Parameter to Enforce DAC on Hardlinks
To set the runtime status of the <code>fs.protected_hardlinks</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w fs.protecte...Rule Medium Severity -
Enable Kernel Parameter to Enforce DAC on Symlinks
To set the runtime status of the <code>fs.protected_symlinks</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w fs.protected...Rule Medium Severity -
Verify Permissions on Files with Local Account Information and Credentials
The default restrictive permissions for files which act as important security databases such as <code>passwd</code>, <code>shadow</code>, <code>gro...Group -
Verify User Who Owns gshadow File
To properly set the owner of/etc/gshadow
, run the command:$ sudo chown root /etc/gshadow
Rule Medium Severity -
Verify User Who Owns shadow File
To properly set the owner of/etc/shadow
, run the command:$ sudo chown root /etc/shadow
Rule Medium Severity -
Verify Permissions on group File
To properly set the permissions of/etc/group
, run the command:$ sudo chmod 0644 /etc/group
Rule Medium Severity -
Verify Permissions on gshadow File
To properly set the permissions of/etc/gshadow
, run the command:$ sudo chmod 0000 /etc/gshadow
Rule Medium Severity -
Verify Permissions on passwd File
To properly set the permissions of/etc/passwd
, run the command:$ sudo chmod 0644 /etc/passwd
Rule Medium Severity -
Verify Permissions on shadow File
To properly set the permissions of/etc/shadow
, run the command:$ sudo chmod 0640 /etc/shadow
Rule Medium Severity -
Restrict Partition Mount Options
System partitions can be mounted with certain options that limit what files on those partitions can do. These options are set in the <code>/etc/fst...Group -
Add noexec Option to /boot
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/boot</code>. Add the <code>noexec</code> op...Rule Medium Severity -
Add nosuid Option to /boot
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/boot</code>. The SUID and SGID permissions shoul...Rule Medium Severity -
Add noexec Option to /home
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/home</code>. Add the <code>noexec</code> opt...Rule Medium Severity -
Add nosuid Option to /home
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/home</code>. The SUID and SGID permissions shoul...Rule Medium Severity -
Add nodev Option to Non-Root Local Partitions
The <code>nodev</code> mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices sho...Rule Medium Severity -
Add nosuid Option to /opt
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/opt</code>. The SUID and SGID permissions should...Rule Medium Severity -
Add nosuid Option to /srv
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/srv</code>. The SUID and SGID permissions should...Rule Medium Severity -
Add noexec Option to /tmp
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/tmp</code>. Add the <code>noexec</code> opti...Rule Medium Severity -
Add nosuid Option to /tmp
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/tmp</code>. The SUID and SGID permissions should...Rule Medium Severity -
Add noexec Option to /var/log
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/var/log</code>. Add the <code>noexec</code> ...Rule Medium Severity -
Add nosuid Option to /var/log
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/var/log</code>. The SUID and SGID permissions sh...Rule Medium Severity -
Add noexec Option to /var
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/var</code>. Add the <code>noexec</code> opti...Rule Medium Severity -
Add nosuid Option to /var
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/var</code>. The SUID and SGID permissions should...Rule Medium Severity -
Add noexec Option to /var/tmp
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/var/tmp</code>. Add the <code>noexec</code> ...Rule Medium Severity -
Add nosuid Option to /var/tmp
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/var/tmp</code>. The SUID and SGID permissions sh...Rule Medium Severity -
Restrict Programs from Dangerous Execution Patterns
The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution ar...Group -
Restrict Access to Kernel Message Buffer
To set the runtime status of the <code>kernel.dmesg_restrict</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.dmesg...Rule Low Severity -
Disable loading and unloading of kernel modules
To set the runtime status of the <code>kernel.modules_disabled</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.mod...Rule Medium Severity -
Kernel panic on oops
To set the runtime status of the <code>kernel.panic_on_oops</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.panic_...Rule Medium Severity -
Limit CPU consumption of the Perf system
To set the runtime status of the <code>kernel.perf_cpu_time_max_percent</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w k...Rule Medium Severity -
Limit sampling frequency of the Perf system
To set the runtime status of the <code>kernel.perf_event_max_sample_rate</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w ...Rule Medium Severity -
Disallow kernel profiling by unprivileged users
To set the runtime status of the <code>kernel.perf_event_paranoid</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel....Rule Low Severity -
Configure maximum number of process identifiers
To set the runtime status of the <code>kernel.pid_max</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.pid_max=6553...Rule Medium Severity -
Disallow magic SysRq key
To set the runtime status of the <code>kernel.sysrq</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.sysrq=0</pre> ...Rule Medium Severity -
Restrict usage of ptrace to descendant processes
To set the runtime status of the <code>kernel.yama.ptrace_scope</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.ya...Rule Medium Severity -
Prevent applications from mapping low portion of virtual memory
To set the runtime status of the <code>vm.mmap_min_addr</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w vm.mmap_min_addr=...Rule Medium Severity -
Disable Core Dumps
A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases,...Group -
Disable Core Dumps for SUID programs
To set the runtime status of the <code>fs.suid_dumpable</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w fs.suid_dumpable=...Rule Medium Severity -
Enable ExecShield
ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These featu...Group -
Restrict Exposed Kernel Pointer Addresses Access
To set the runtime status of the <code>kernel.kptr_restrict</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.kptr_r...Rule Medium Severity -
Enable Randomized Layout of Virtual Address Space
To set the runtime status of the <code>kernel.randomize_va_space</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.r...Rule Medium Severity
Node 2
The content of the drawer really is up to you. It could have form fields, definition lists, text lists, labels, charts, progress bars, etc. Spacing recommendation is 24px margins. You can put tabs in here, and can also make the drawer scrollable.