On Tuesday, October 27, 2015 10:00:07 AM Robert Jacobson wrote:
I've recently been trying to reconcile the audit.rules on my
systems vs.
the scap-security-guide, and I'm confused about the ARCH rules.
Right. I sent feedback internally to the project to tell them that what is
written is not efficient and not clear. That section is being re-written.
When is it required to check both 32- and 64-bit architectures?
Whenever you have a system that is bi-arch. That would commonly be 64 bit
systems. But it is possible to compile 64 bit kernels that have no 32 bit ABI.
e.g. the guide says both 32- and 64-bit rules are required to check
for
unauthorized access attempts:
That is a fact. The stig.rules shipped in the audit package is an accurate
starting point for 64 bit systems needing stig compliance.
# Unauthorized Access attempts
(audit_rules_unsuccessful_file_modification)
-a always,exit -F arch=b32 -S creat -S open -S openat -S
open_by_handle_at -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
open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500
-F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S
open_by_handle_at -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
open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500
-F auid!=4294967295 -k access
This looks correct assuming that real users start at 500. That number needs
adjusting up if you start users at a higher number.
But for modifying the network environment, only the 64-bit rule is
required:
# Network changes ( audit_rules_networkconfig_modification )
-a always,exit -F arch=b64 -S sethostname -S setdomainname -k
audit_rules_networkconfig_modification
A 32 bit rule is also needed.
I don't understand why the 32-bit check is required for open()
calls but
not sethostname() calls?
Its a mistake. I am working with them to correct the SSG and it has problems
beyond auditing. But its being patched quickly and should be ready to use
soon.
-Steve