Windows Multiple Users Failed To Authenticate From Process

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Description

The following analytic detects a source process failing to authenticate with 30 unique users, indicating a potential Password Spraying attack. It leverages Windows Event 4625 with Logon Type 2, collected from domain controllers, member servers, and workstations. This activity is significant as it may represent an adversary attempting to gain initial access or elevate privileges within an Active Directory environment. If confirmed malicious, this could lead to unauthorized access, privilege escalation, or further compromise of the network, posing a severe security risk.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2024-05-25
• Author: Mauricio Velazco, Splunk
• ID: 9015385a-9c84-11eb-bef2-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1110.003	Password Spraying	Credential Access

T1110

Brute Force

Credential Access

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

 `wineventlog_security` EventCode=4625 Logon_Type=2 ProcessName!="-" 
| bucket span=5m _time 
| stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as tried_accounts by _time, ProcessName, SubjectUserName, Computer 
| rename Computer as dest 
| where unique_accounts > 30 
| `windows_multiple_users_failed_to_authenticate_from_process_filter`

Macros

The SPL above uses the following Macros:

• wineventlog_security

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

Required fields

List of fields required to use this analytic.

• _time
• EventCode
• Logon_Type
• ProcessName
• SubjectUserName
• TargetUserName
• Computer

How To Implement

To successfully implement this search, you need to be ingesting Windows Event Logs from domain controllers aas 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 process failing to authenticate with multiple users is not a common behavior for legitimate user sessions. Possible false positive scenarios include but are not limited to vulnerability scanners and missconfigured systems.

Associated Analytic Story

• Active Directory Password Spraying
• Insider Threat
• Volt Typhoon

RBA

Risk Score	Impact	Confidence	Message
49.0	70	70	Potential password spraying attack from $dest$

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

Reference

• https://attack.mitre.org/techniques/T1110/003/
• https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4625
• https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4625
• https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/basic-audit-logon-events

Test Dataset

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 | version: 3