Guide to the Secure Configuration of Red Hat Enterprise Linux 7
with profile Common Profile for General-Purpose Systems
Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG for RHEL 7 is one example of a baseline created from this guidance.
Profile Title | Common Profile for General-Purpose Systems |
---|---|
Profile ID | xccdf_org.ssgproject.content_profile_common |
Revision History
Current version: 0.9
- draft (as of 2015-07-30)
Platforms
- cpe:/o:redhat:enterprise_linux:7
- cpe:/o:redhat:enterprise_linux:7::client
Table of Contents
- System Settings
- Installing and Maintaining Software
- File Permissions and Masks
- Configure Syslog
- System Accounting with auditd
- Services
Checklist
contains 38 rules |
System Settingsgroup |
contains 32 rules |
Installing and Maintaining SoftwaregroupThe following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates. |
contains 2 rules |
Disk PartitioninggroupTo ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
|
contains 2 rules |
Ensure /var/log Located On Separate Partitionrule
System logs are stored in the
Placing identifiers: CCE-26967-0 references: AU-9, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20120928 by MM |
Ensure /var/log/audit Located On Separate Partitionrule
Audit logs are stored in the
Placing identifiers: CCE-26971-2 references: AU-4, AU-9, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20120928 by MM |
File Permissions and MasksgroupTraditional Unix security relies heavily on file and
directory permissions to prevent unauthorized users from reading or
modifying files to which they should not have access.
$ mount -t xfs | awk '{print $3}'For any systems that use a different local filesystem type, modify this command as appropriate. |
contains 1 rule |
Restrict Dynamic Mounting and Unmounting of FilesystemsgroupLinux includes a number of facilities for the automated addition
and removal of filesystems on a running system. These facilities may be
necessary in many environments, but this capability also carries some risk -- whether direct
risk from allowing users to introduce arbitrary filesystems,
or risk that software flaws in the automated mount facility itself could
allow an attacker to compromise the system.
$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'If these filesystems are not required then they can be explicitly disabled in a configuratio file in /etc/modprobe.d .
|
contains 1 rule |
Disable the AutomounterruleThe $ sudo systemctl disable autofsRationale: Disabling the automounter permits the administrator to
statically control filesystem mounting through identifiers: CCE-RHEL7-CCE-TBD references: AC-19(a), AC-19(d), AC-19(e), 1250, 85 Remediation script:
|
Configure SysloggroupThe syslog service has been the default Unix logging mechanism for
many years. It has a number of downsides, including inconsistent log format,
lack of authentication for received messages, and lack of authentication,
encryption, or reliable transport for messages sent over a network. However,
due to its long history, syslog is a de facto standard which is supported by
almost all Unix applications.
|
contains 2 rules |
Ensure rsyslog is Installedrule
Rsyslog is installed by default.
The $ sudo yum install rsyslogRationale: The rsyslog package provides the rsyslog daemon, which provides system logging services. identifiers: CCE-RHEL7-CCE-TBD references: AU-9(2), 1311, 1312, Test attestation on 20121024 by DS Remediation script:
|
Enable rsyslog ServiceruleThe $ sudo systemctl enable rsyslogRationale: The identifiers: CCE-RHEL7-CCE-TBD references: AU-12, 1557, 1312, 1311, Test attestation on 20121024 by DS Remediation script:
|
System Accounting with auditdgroupThe audit service provides substantial capabilities
for recording system activities. By default, the service audits about
SELinux AVC denials and certain types of security-relevant events
such as system logins, account modifications, and authentication
events performed by programs such as sudo.
Under its default configuration, ExecStartPost=-/sbin/augenrules --loadin the /usr/lib/systemd/system/auditd.service configuration file.
In order to instruct the auditd daemon to use the auditctl
utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rulesin the /usr/lib/systemd/system/auditd.service configuration file.
Refer to [Service] section of the /usr/lib/systemd/system/auditd.service
configuration file for further details.
Government networks often have substantial auditing requirements and auditd can be configured to meet these
requirements.
Examining some example audit records demonstrates how the Linux audit system
satisfies common requirements.
The following example from Fedora Documentation available at
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/SELinux_Users_and_Administrators_Guide/sect-Security-Enhanced_Linux-Troubleshooting-Fixing_Problems.html#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages
shows the substantial amount of information captured in a
two typical "raw" audit messages, followed by a breakdown of the most important
fields. In this example the message is SELinux-related and reports an AVC
denial (and the associated system call) that occurred when the Apache HTTP
Server attempted to access the /var/www/html/file1 file (labeled with
the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc: denied { getattr } for pid=2465 comm="httpd" path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13 a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48 gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd" exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
|
contains 27 rules |
Configure auditd Rules for Comprehensive AuditinggroupThe
Auditing rules at startup are controlled by the file /etc/audit/audit.rules .
Add rules to it to meet the auditing requirements for your organization.
Each line in /etc/audit/audit.rules represents a series of arguments
that can be passed to auditctl and can be individually tested
during runtime. See documentation in /usr/share/doc/audit-VERSION and
in the related man pages for more details.
If copying any example audit rulesets from /usr/share/doc/audit-VERSION ,
be sure to comment out the
lines containing arch= which are not appropriate for your system's
architecture. Then review and understand the following rules,
ensuring rules are activated as needed for the appropriate
architecture.
After reviewing all the rules, reading the following sections, and editing as needed, the new rules can be activated as follows: $ sudo service auditd restart |
contains 27 rules |
Records Events that Modify Date and Time InformationgroupArbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All changes to the system time should be audited. |
contains 5 rules |
Record attempts to alter time through adjtimexruleIf the -a always,exit -F arch=b32 -S adjtimex -k audit_time_rulesIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S adjtimex -k audit_time_rulesIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -k audit_time_rulesIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S adjtimex -k audit_time_rulesThe -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rulesRationale: Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 |
Record attempts to alter time through settimeofdayruleIf the -a always,exit -F arch=b32 -S settimeofday -k audit_time_rulesIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S settimeofday -k audit_time_rulesIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S settimeofday -k audit_time_rulesIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S settimeofday -k audit_time_rulesThe -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rulesRationale: Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 |
Record Attempts to Alter Time Through stimeruleIf the -a always,exit -F arch=b32 -S stime -k audit_time_rulesSince the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the auditctl utility to
read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -k audit_time_rulesSince the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rulesRationale: Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 |
Record Attempts to Alter Time Through clock_settimeruleIf the -a always,exit -F arch=b32 -S clock_settime -k audit_time_rulesIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S clock_settime -k audit_time_rulesIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -k audit_time_rulesIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S clock_settime -k audit_time_rulesThe -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rulesRationale: Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169 |
Record Attempts to Alter the localtime FileruleIf the -w /etc/localtime -p wa -k audit_time_rulesIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rulesThe -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used. Rationale: Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(b), IR-5, 1487, 169 Remediation script:
|
Record Events that Modify the System's Discretionary Access ControlsgroupAt a minimum the audit system should collect file permission
changes for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to -a always,exit -F arch=b32 -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod -a always,exit -F arch=b32 -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod -a always,exit -F arch=b32 -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows: -a always,exit -F arch=b64 -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod -a always,exit -F arch=b64 -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod -a always,exit -F arch=b64 -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod |
contains 13 rules |
Record Events that Modify the System's Discretionary Access Controls - chmodruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - chownruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - fchmodruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - fchmodatruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - fchownruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - fchownatruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattrruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattrruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Record Events that Modify the System's Discretionary Access Controls - lchownruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Record Events that Modify the System's Discretionary Access Controls - lremovexattrruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Record Events that Modify the System's Discretionary Access Controls - lsetxattrruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Record Events that Modify the System's Discretionary Access Controls - removexattrruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Record Events that Modify the System's Discretionary Access Controls - setxattrruleAt a minimum the audit system should collect file permission
changes for all users and root. If the -a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_modIf the system is 64 bit then also add the following line: -a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod warning
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient.
The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Record Events that Modify User/Group InformationruleIf the -w /etc/group -p wa -k audit_rules_usergroup_modification -w /etc/passwd -p wa -k audit_rules_usergroup_modification -w /etc/gshadow -p wa -k audit_rules_usergroup_modification -w /etc/shadow -p wa -k audit_rules_usergroup_modification -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modificationIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification -w /etc/passwd -p wa -k audit_rules_usergroup_modification -w /etc/gshadow -p wa -k audit_rules_usergroup_modification -w /etc/shadow -p wa -k audit_rules_usergroup_modification -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modificationRationale: In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy. identifiers: CCE-27192-4 references: AC-2(4), AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 18, 172, 1403, 1404, 1405, 1684, 1683, 1685, 1686, 476, 239 Remediation script:
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Record Events that Modify the System's Network EnvironmentruleIf the -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification -w /etc/issue -p wa -k audit_rules_networkconfig_modification -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification -w /etc/hosts -p wa -k audit_rules_networkconfig_modification -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modificationIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification -w /etc/issue -p wa -k audit_rules_networkconfig_modification -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification -w /etc/hosts -p wa -k audit_rules_networkconfig_modification -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modificationRationale: The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5 Remediation script:
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Record Events that Modify the System's Mandatory Access ControlsruleIf the -w /etc/selinux/ -p wa -k MAC-policyIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policyRationale: The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5 Remediation script:
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Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)ruleAt a minimum the audit system should collect unauthorized file
accesses for all users and root. If the -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k accessIf the system is 64 bit then also add the following lines: -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k accessIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k accessIf the system is 64 bit then also add the following lines: -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k accessRationale: Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126 Remediation script:
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Ensure auditd Collects Information on the Use of Privileged CommandsruleAt a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART: $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/nullIf the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add a line of
the following form to a file with suffix .rules in the directory
/etc/audit/rules.d for each setuid / setgid program on the system,
replacing the SETUID_PROG_PATH part with the full path of that setuid /
setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=4294967295 -k privilegedIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules for each setuid / setgid program on the
system, replacing the SETUID_PROG_PATH part with the full path of that
setuid / setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=4294967295 -k privilegedRationale: Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-2(4), AU-12(a), AU-12(c), IR-5, 40, Test attestation on 20121024 by DS |
Ensure auditd Collects Information on Exporting to Media (successful)ruleAt a minimum the audit system should collect media exportation
events for all users and root. If the -a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k exportIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k exportRationale: The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126, Test attestation on 20121024 by DS Remediation script:
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Ensure auditd Collects File Deletion Events by UserruleAt a minimum the audit system should collect file deletion events
for all users and root. If the -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k deleteIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k deleteRationale: Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence. identifiers: CCE-27206-2 references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 172, 468 Remediation script:
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Ensure auditd Collects System Administrator ActionsruleAt a minimum the audit system should collect administrator actions
for all users and root. If the -w /etc/sudoers -p wa -k actionsIf the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actionsRationale: The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes. identifiers: CCE-RHEL7-CCE-TBD references: AC-2(7)(b), AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126, Test attestation on 20121024 by DS Remediation script:
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Ensure auditd Collects Information on Kernel Module Loading and UnloadingruleIf the -w /usr/sbin/insmod -p x -k modules -w /usr/sbin/rmmod -p x -k modules -w /usr/sbin/modprobe -p x -k modules -a always,exit -F arch=ARCH -S init_module -S delete_module -k modulesIf the auditd daemon is configured to use the auditctl utility to read audit
rules during daemon startup, add the following lines to /etc/audit/audit.rules file
in order to capture kernel module loading and unloading events, setting ARCH to either b32 or
b64 as appropriate for your system:
-w /usr/sbin/insmod -p x -k modules -w /usr/sbin/rmmod -p x -k modules -w /usr/sbin/modprobe -p x -k modules -a always,exit -F arch=ARCH -S init_module -S delete_module -k modulesRationale: The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel. identifiers: CCE-27129-6 references: AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 172, 477 Remediation script:
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Servicesgroup
The best protection against vulnerable software is running less software. This section describes how to review
the software which Red Hat Enterprise Linux 7 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default RHEL 7 system and provides guidance about which
ones can be safely disabled.
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contains 6 rules |
Base ServicesgroupThis section addresses the base services that are installed on a RHEL 7 default installation which are not covered in other sections. Some of these services listen on the network and should be treated with particular discretion. Other services are local system utilities that may or may not be extraneous. In general, system services should be disabled if not required. |
contains 5 rules |
Disable Automatic Bug Reporting Tool (abrtd)ruleThe Automatic Bug Reporting Tool ( $ sudo systemctl disable abrtdRationale: Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the local machine, as well as sensitive information from within a process's address space or registers. identifiers: CCE-26872-2 references: AC-17(8), CM-7, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20140921 by JL Remediation script:
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Disable ntpdate Service (ntpdate)ruleThe $ sudo systemctl disable ntpdateRationale: The identifiers: CCE-RHEL7-CCE-TBD references: AC-17(8), CM-7, 382, Test attestation on 20121024 by DS |
Disable Odd Job Daemon (oddjobd)ruleThe $ sudo systemctl disable oddjobdRationale: The identifiers: CCE-RHEL7-CCE-TBD references: CM-7, 381, Test attestation on 20121024 by DS Remediation script:
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Disable Apache Qpid (qpidd)ruleThe $ sudo systemctl disable qpiddRationale: The qpidd service is automatically installed when the "base"
package selection is selected during installation. The qpidd service listens
for network connections, which increases the attack surface of the system. If
the system is not intended to receive AMQP traffic, then the identifiers: CCE-RHEL7-CCE-TBD references: AC-17(8), CM-7, 382 Remediation script:
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Disable Network Router Discovery Daemon (rdisc)ruleThe $ sudo systemctl disable rdiscRationale: General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information. identifiers: CCE-RHEL7-CCE-TBD references: AC-17(8), AC-4, CM-7, 382, Test attestation on 20121024 by DS Remediation script:
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Cron and At DaemonsgroupThe cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively. |
contains 1 rule |
Disable At Service (atd)ruleThe $ sudo systemctl disable atdRationale:
The identifiers: CCE-RHEL7-CCE-TBD Remediation script:
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