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-000064-GPOS-00033, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000474-GPOS-00219
Solution
Navigate to and open:
/etc/audit/rules.d/audit.STIG.rules
Add or update the following lines:
-a always,exit -F arch=b64 -S chmod,fchmod,chown,fchown,lchown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S chmod,fchmod,chown,fchown,lchown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F auid=0 -F key=perm_mod
-a always,exit -F arch=b32 -S chmod,lchown,fchmod,fchown,chown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S chmod,lchown,fchmod,fchown,chown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F auid=0 -F key=perm_mod
At the command line, run the following command to load the new audit rules:
# /sbin/augenrules --load
Note: An "audit.STIG.rules" file is provided with this guidance for placement in "/etc/audit/rules.d" that contains all rules needed for auditd.
Note: An older "audit.STIG.rules" may exist and may reference older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one.