4.1.2.4 Ensure audit_backlog_limit is sufficient

Information

The backlog limit has a default setting of 64

Rationale:

During boot if audit=1, then the backlog will hold 64 records. If more than 64 records are created during boot, auditd records will be lost and potential malicious activity could go undetected.

Solution

Edit /boot/grub/grub.conf or /boot/efi/EFI/*/grub.conf on UEFI systems and add audit_backlog_limit=<BACKLOG SIZE> to each line beginning with kernel:
Example:

[ -f /boot/efi/EFI/*/grub.conf ] && sed -ri 's/(^s*kernels+.*)$/1 audit_backlog_limit=8192/g' /boot/efi/EFI/*/grub.conf || sed -ri 's/(^s*kernels+.*)$/1 audit_backlog_limit=8192/g' /boot/grub/grub.conf

See Also

https://workbench.cisecurity.org/files/3148

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-3, 800-53|AU-12, CSCv7|6.2, CSCv7|6.3

Plugin: Unix

Control ID: d50a2a35c1c600f6b34af4cf7257f94526a4e0c13df7d3f9c8485125d0bc9f03