Cross-source coverage

T1078.001 / ATT&CK

Valid Accounts: Default Accounts

13 rules across 4 sources.

From MITRE ATT&CK 19.2

Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the root user account in AWS, the root user account in ESXi, and the default service account in Kubernetes.

Default accounts are not limited to client machines; rather, they also include accounts that are preset for equipment such as network devices and computer applications, whether they are internal, open source, or commercial. Appliances that come preset with a username and password combination pose a serious threat to organizations that do not change it post installation, as they are easy targets for an adversary. Similarly, adversaries may also utilize publicly disclosed or stolen Private Keys or credential materials to legitimately connect to remote environments via Remote Services.

Default accounts may be created on a system after initial setup by connecting or integrating it with another application. For example, when an ESXi server is connected to a vCenter server, a default privileged account called vpxuser is created on the ESXi server. If a threat actor is able to compromise this account’s credentials (for example, via Exploitation for Credential Access on the vCenter host), they will then have access to the ESXi server.

Platforms
Containers · ESXi · IaaS · Identity Provider · Linux · macOS · Network Devices · Office Suite · SaaS · Windows
Telemetry
WinEventLog:Securityauditd:USER_LOGINAWS:CloudTrailesxi:authnetworkdevice:syslog

How MITRE says to detect it DET0465

Detection of Default Account Abuse Across Platforms

Windows Analytic 1283

Detection of default account usage such as Guest or Administrator performing interactive or remote logons on systems outside of installation or maintenance windows.

  • WinEventLog:Security EventCode=4624, 4648

Linux Analytic 1284

Monitoring for SSH logins from default accounts such as 'root', especially when login is via password and not key-based authentication.

  • auditd:USER_LOGIN USER_LOGIN

Identity Provider Analytic 1285

Use of known default service accounts or root-level cloud accounts performing authentication or changes to IAM policy.

  • AWS:CloudTrail ConsoleLogin or AssumeRole

ESXi Analytic 1286

Abuse of system-generated or default privileged accounts such as 'root' or 'vpxuser' logging into ESXi hosts.

  • esxi:auth /var/log/auth.log

Network Devices Analytic 1287

Login activity from default admin credentials (e.g., 'admin', 'cisco') on routers, firewalls, and switches.

  • networkdevice:syslog authentication logs

SigmaHQ/sigma

4 rules
Detection Severity Format
Commvault QLogin with PublicSharingUser and GUID Password (CVE-2025-57788) Medium Sigma
Root Account Enable Via Dsenableroot Medium Sigma
Admin User Remote Logon Low Sigma
Guest Account Enabled Via Sysadminctl Low Sigma

elastic/detection-rules

4 rules
Detection Severity Format
GKE Anonymous Request Authorized by Unusual User Agent Medium Elastic TOML
GKE Suspicious Assignment of Controller Service Account Medium Elastic TOML
Kubernetes Anonymous Request Authorized by Unusual User Agent Medium Elastic TOML
Kubernetes Suspicious Assignment of Controller Service Account Medium Elastic TOML

splunk/security_content

4 rules
Detection Severity Format
Okta New API Token Created Undefined SPL
Okta Phishing Detection with FastPass Origin Check Undefined SPL
Okta Suspicious Activity Reported Undefined SPL
Windows Guest Account Enabled Via Net.EXE Undefined SPL

panther-labs/panther-analysis

1 rule
Detection Severity Format
Snowflake Grant to Public Role Medium Panther Python

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