4.1.4 Ensure events that modify date and time information are collected - auditctl /etc/localtime

Information

Capture events where the system date and/or time has been modified. The parameters in this section are set to determine if the adjtimex (tune kernel clock), settimeofday (Set time, using timeval and timezone structures) stime (using seconds since 1/1/1970) or clock_settime (allows for the setting of several internal clocks and timers) system calls have been executed and always write an audit record to the /var/log/audit.log file upon exit, tagging the records with the identifier 'time-change'

Rationale:

Unexpected changes in system date and/or time could be a sign of malicious activity on the system.

Solution

For 32 bit systems add the following lines to the /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k time-change
-a always,exit -F arch=b32 -S clock_settime -k time-change
-w /etc/localtime -p wa -k time-change

For 64 bit systems add the following lines to the /etc/audit/audit.rules file:

-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k time-change
-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k time-change
-a always,exit -F arch=b64 -S clock_settime -k time-change
-a always,exit -F arch=b32 -S clock_settime -k time-change
-w /etc/localtime -p wa -k time-change

Impact:

Auditing can produce a large amount of information, creating large and/or many audit log files.

Notes:

Reloading the auditd config to set active settings may require a system reboot.

See Also

https://workbench.cisecurity.org/files/2619

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, CSCv7|5.5

Plugin: Unix

Control ID: efdc608ef15b232cc0142734a208421e3c921195f412fd281f763d03dd5ffcf8