RHEL-07-030440 - The Red Hat Enterprise Linux operating system must audit all uses of the setxattr, fsetxattr, lsetxattr, removexattr, fremovexattr, and lremovexattr syscalls.

Information

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Audit records can be generated from various components within the information system (e.g., module or policy filter).

When a user logs on, the auid is set to the uid of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to -1. The auid representation is an unsigned 32-bit integer, which equals 4294967295. The audit system interprets -1, 4294967295, and 'unset' in the same way.

The system call rules are loaded into a matching engine that intercepts each syscall made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining syscalls into one rule whenever possible.

Satisfies: SRG-OS-000458-GPOS-00203, SRG-OS-000392-GPOS-00172, SRG-OS-000064-GPOS-00033

Solution

Configure the operating system to generate audit records upon successful/unsuccessful attempts to use the 'setxattr', 'fsetxattr', 'lsetxattr', 'removexattr', 'fremovexattr', and 'lremovexattr' syscalls.

Add or update the following rules in '/etc/audit/rules.d/audit.rules':

-a always,exit -F arch=b32 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod

-a always,exit -F arch=b64 -S setxattr,fsetxattr,lsetxattr,removexattr,fremovexattr,lremovexattr -F auid>=1000 -F auid!=unset -k perm_mod

The audit daemon must be restarted for the changes to take effect.

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_7_V3R15_STIG.zip

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-12c., CAT|II, CCI|CCI-000172, Rule-ID|SV-204524r991570_rule, STIG-ID|RHEL-07-030440, STIG-Legacy|SV-86735, STIG-Legacy|V-72111, Vuln-ID|V-204524

Plugin: Unix

Control ID: c4c40dceae83e7e0744cf385e08ab20c6edbdc517266312ebf431d2ace1594b2