Cyber Posture

NIST 800-53 r5 · Controls catalogue · Family AC

AC-9Previous Logon Notification

Notify the user, upon successful logon to the system, of the date and time of the last logon.

Last updated: 09 May 2026 03:25 UTC

Implementations targeting this control (0)

ATT&CK techniques this control mitigates (0)

Weaknesses this control addresses (6)AI

CWEs ranked by how often they appear in real CVEs. The rationale describes how this control reduces exploitability of each weakness class.

CWE Name CVEs Why this control addresses it
CWE-287Improper Authentication4,730Detects unauthorized successful logons resulting from improper authentication implementations.
CWE-798Use of Hard-coded Credentials1,955Enables users to notice when hard-coded credentials have been exploited for unauthorized access.
CWE-290Authentication Bypass by Spoofing631Reveals spoofed logon attempts through unexpected previous logon timestamps upon legitimate login.
CWE-288Authentication Bypass Using an Alternate Path or Channel523Users can identify logons via alternate paths or channels by reviewing the previous logon time.
CWE-294Authentication Bypass by Capture-replay264Allows detection of capture-replay attacks by showing the replayed logon's timestamp as the last logon.
CWE-1390Weak Authentication75Helps detect exploitation of weak authentication mechanisms by notifying of previous unauthorized logons.

Top CVEs where this control is the strongest mitigation

CVE Risk CVSS EPSS Match
CVE-2024-421760.52.60.0016partial

Other controls in family AC

AC-1 AC-10 AC-11 AC-12 AC-13 AC-14 AC-15 AC-16 AC-17 AC-18 AC-19 AC-2 AC-20 AC-21 AC-22 AC-23 AC-24 AC-25 AC-3 AC-4 AC-5 AC-6 AC-7 AC-8