Password Guessing via Multi-Source Authentication Failure Correlation

Technique Detected:  Password Guessing | T1110.001

ID: DET0551
Domains: Enterprise
Analytics: AN1521, AN1522, AN1523, AN1524, AN1525, AN1526
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN1521

Series of authentication failures (Event ID 4625) targeting the same or similar user accounts over time from one or more remote IPs

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) WinEventLog:Security EventCode=4625
Mutable Elements
Field Description
TimeWindow Defines the period in which multiple failed attempts are aggregated (e.g., 10 minutes)
UsernamePattern Filter for common account naming conventions, e.g., service accounts or administrator variants
SourceIPThreshold Limit on unique IPs trying to authenticate against a single account

AN1522

Repeated failed SSH login attempts followed by a possible success from the same remote host

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) linux:syslog sshd[pid]: Failed password
Mutable Elements
Field Description
PortScope Can be tuned to non-standard ports if SSH is moved from default
UserScope Filter high-value or restricted users (e.g., root, service)
AttemptThreshold Number of consecutive failures before flagging (e.g., >5 in 2 minutes)

AN1523

Series of failed logins from loginwindow or sshd with repeated usernames or password prompts

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) macos:unifiedlog authd
Mutable Elements
Field Description
AuthMechanism Local console vs. SSH vs. remote Apple Admin tools
FailurePattern Use regex to isolate brute force messages among other log noise

AN1524

Multiple failed sign-in attempts from external sources across many users followed by success from the same IP

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) azure:signinlogs Sign-in logs
Mutable Elements
Field Description
GeoRiskScore Elevate anomalies from uncommon geolocations
MFAStatus Elevate logins missing MFA on high-value accounts

AN1525

Login attempt failures over SNMP, Telnet, or SSH interface, often reflected in logs or syslog events

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) networkdevice:syslog login failed
Mutable Elements
Field Description
InterfaceType Specify monitoring of Telnet/SSH/SNMP for login activity
FailedAttemptThreshold How many failures in short succession should trigger alerting

AN1526

Password guessing attempts against web-based apps (e.g., Dropbox, Google Workspace) reflected in API or sign-in logs

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) GCPAuditLogs:login.googleapis.com Failed sign-in events
Mutable Elements
Field Description
AppContext Which SaaS apps should be monitored for brute force attempts
EmailPattern Limit scope to enterprise domains or service accounts