Detections
Analytics
4.1.7 Ensure events that modify the system's network environment are collected - /etc/hosts
Information
Record changes to network environment files or system calls. The below parametersmonitor the sethostname (set the systems host name) or setdomainname (set the systems
domainname) system calls, and write an audit event on system call exit. The other
parameters monitor the /etc/issue and /etc/issue.net files (messages displayed pre-
login), /etc/hosts (file containing host names and associated IP addresses) and
/etc/sysconfig/network (directory containing network interface scripts and
configurations) files.
Rationale:
Monitoring sethostname and setdomainname will identify potential unauthorized changes
to host and domainname of a system. The changing of these names could potentially break
security parameters that are set based on those names. The /etc/hosts file is monitored
for changes in the file that can indicate an unauthorized intruder is trying to change
machine associations with IP addresses and trick users and processes into connecting to
unintended machines. Monitoring /etc/issue and /etc/issue.net is important, as
intruders could put disinformation into those files and trick users into providing
information to the intruder. Monitoring /etc/sysconfig/network is important as it can
show if network interfaces or scripts are being modified in a way that can lead to the
machine becoming unavailable or compromised. All audit records will be tagged with the
identifier "system-locale."
Solution
For 32 bit systems Edit or create a file in the /etc/audit/rules.d/ directory ending in.rules
Example: vi /etc/audit/rules.d/audit.rules
and add the following lines:
-a always,exit -F arch=b32 -S sethostname -S setdomainname -k system-locale
-w /etc/issue -p wa -k system-locale
-w /etc/issue.net -p wa -k system-locale
-w /etc/hosts -p wa -k system-locale
-w /etc/sysconfig/network -p wa -k system-locale
For 64 bit systems Edit or create a file in the /etc/audit/rules.d/ directory ending in
.rules
Example: vi /etc/audit/rules.d/audit.rules
and add the following lines:
-a always,exit -F arch=b64 -S sethostname -S setdomainname -k system-locale
-a always,exit -F arch=b32 -S sethostname -S setdomainname -k system-locale
-w /etc/issue -p wa -k system-locale
-w /etc/issue.net -p wa -k system-locale
-w /etc/hosts -p wa -k system-locale
-w /etc/sysconfig/network -p wa -k system-locale
Notes:
/etc/sysconfig/network is common to Red Hat and SUSE based distributions.
You should expand or replace this coverage to any network configuration files on your
system such as /etc/network on Debian based distributions.
Reloading the auditd config to set active settings may require a system reboot.
See Also
Item Details
Category: CONFIGURATION MANAGEMENT
References: 800-53|CM-6, CSCv6|3.6, CSCv7|5.5
Plugin: Unix
Control ID: b2cdcb03b12a2eb54f2e86493290a5fe480095f5953a83046833fb2ad7433906