[ 1. COMPLIANCE & THREAT PROFILES ]

Telemetry Rate & Impact
Est. ~45 events/sec · ~120 MB/day
[ BALANCED COMPLIANCE ]

[ 2. BUFFER & KERNEL CONTROL FLAGS ]

Size of the kernel netlink audit queue buffer to prevent audit message loss under high load.
Action taken by the Linux kernel if the audit backlog buffer overflows.
Enable kernel immutable mode to prevent attackers from disabling audit rules until reboot.
[ SUBSYSTEM WATCH DIRECTIVES ]
# Generating Linux Auditd configuration...
[ NOTE // IMMUTABILITY ]: When -e 2 is active, the audit configuration is locked in kernel memory. Any attempt to modify or delete rules via auditctl will be rejected until the system is rebooted.

Architecture: Linux Kernel Audit Subsystem & DFIR Telemetry

The Linux Audit Framework (auditd) operates at the kernel boundary via a dedicated Netlink socket, intercepting system calls before execution and generating high-integrity security telemetry. Unlike user-space logging daemons (such as standard syslog), kernel audit events cannot be bypassed by unprivileged users or stripped from process memory.

Key Audit Ruleset Dimensions

Process Injection & ptrace Defense

Attackers frequently use ptrace or memory dumping tools to extract credentials from memory (e.g. LSASS or SSH keys). Auditing ptrace, process_vm_readv, and process_vm_writev triggers immediate forensic alerts when unprivileged processes attempt inter-process memory inspection.

Immutable Kernel Lock (-e 2)

Placing -e 2 as the final line in /etc/audit/rules.d/audit.rules locks the audit configuration permanently in kernel space. Even an attacker who achieves full root privileges cannot disable the audit daemon or clear the active rule table without a hardware reboot.

Forensic Investigation with ausearch & aureport

Query audit logs efficiently using key tags without parsing raw log files:

# Search all unauthorized file access failures:
$ sudo ausearch --success no --interpret

# Search for all executions tagged with 'exec_commands':
$ sudo ausearch -k exec_commands --interpret

# Generate an executive forensic summary of authentication events:
$ sudo aureport --auth --summary

# Track changes to user identities and passwords:
$ sudo ausearch -k identity -ts today