Detection: Windows Multiple Users Remotely Failed To Authenticate From Host

Updated Date: 2024-09-24 ID: 80f9d53e-9ca1-11eb-b0d6-acde48001122 Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies a source host failing to authenticate against a remote host with 30 unique users. It leverages Windows Event 4625 with Logon Type 3, indicating remote authentication attempts. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges in an Active Directory environment. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, and potential compromise of sensitive information. This detection is crucial for real-time security monitoring and threat hunting.

Search

1`wineventlog_security` EventCode=4625 Logon_Type=3 IpAddress!="-" 
2| bucket span=5m _time 
3| stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as tried_accounts by _time, IpAddress, Computer 
4| rename Computer as dest
5| where unique_accounts > 30 
6| `windows_multiple_users_remotely_failed_to_authenticate_from_host_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Windows Event Log Security 4625	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`	N/A

Macros Used

Name	Value
wineventlog_security	`eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security`
windows_multiple_users_remotely_failed_to_authenticate_from_host_filter	`search *`

windows_multiple_users_remotely_failed_to_authenticate_from_host_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1110.003	Password Spraying	Credential Access
T1110	Brute Force	Credential Access

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_10

APT28

APT29

APT33

Chimera

HEXANE

Lazarus Group

Leafminer

Silent Librarian

APT28

APT38

APT39

DarkVishnya

Dragonfly

FIN5

Fox Kitten

HEXANE

OilRig

Turla

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you need to be ingesting Windows Event Logs from domain controllers as as well as member servers and workstations. The Advanced Security Audit policy setting Audit Logon within Logon/Logoff needs to be enabled.

Known False Positives

A host failing to authenticate with multiple valid users against a remote host is not a common behavior for legitimate systems. Possible false positive scenarios include but are not limited to vulnerability scanners, remote administration tools, missconfigyred systems, etc.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Potential password spraying attack on $dest$	49	70	70

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 4