Information
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.
Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
Solution
Configure the audit system to generate an audit event for any successful/unsuccessful use of the umount system call by adding or updating the following rules in "/etc/audit/audit.rules" and adding the following rules to "/etc/audit/rules.d/perm_mod.rules" or updating the existing rules in files in the "/etc/audit/rules.d/" directory:
-a always,exit -F arch=b32 -S umount -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S umount -F auid>=1000 -F auid!=unset -k perm_mod
The audit daemon must be restarted for the changes to take effect.
Restart auditd:
$ sudo service auditd restart
Item Details
Category: AUDIT AND ACCOUNTABILITY, MAINTENANCE
References: 800-53|AU-3, 800-53|AU-12a., 800-53|AU-12c., 800-53|MA-4(1)(a), CAT|II, CCI|CCI-000130, CCI|CCI-000169, CCI|CCI-000172, CCI|CCI-002884, Rule-ID|SV-271594r1155314_rule, STIG-ID|OL09-00-000840, Vuln-ID|V-271594
Control ID: fa01e9afe7ade474956d96754b58220d6be1d32de42193741a1f9d63baf0d563