4.1.12 Ensure unsuccessful unauthorized file access attempts are collected - b32 EACCES

Information

Monitor for unsuccessful attempts to access files. The parameters below are associated
with system calls that control creation ( creat ), opening ( open , openat ) and truncation (
truncate , ftruncate ) of files. An audit log record will only be written if the user is a non-
privileged user (auid > = 500), is not a Daemon event (auid=4294967295) and if the system
call returned EACCES (permission denied to the file) or EPERM (some other permanent
error associated with the specific system call). All audit records will be tagged with the
identifier "access."

Rationale:

Failed attempts to open, create or truncate files could be an indication that an individual or
process is trying to gain unauthorized access to the system.

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 creat -S open -S openat -S truncate -S
ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S
ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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 creat -S open -S openat -S truncate -S
ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S
ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S truncate -S
ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S
ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

Notes:

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

See Also

https://workbench.cisecurity.org/files/2420

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-3, CSCv6|14.6, CSCv7|14.9

Plugin: Unix

Control ID: 7697700bd55153361d29490826cf785ba762c326c2a6d534786a0acd0ac59a25