Technique on mitre.org

T1087: Account Discovery

Adversaries may attempt to get a listing of valid accounts, usernames, or email addresses on a system or within a compromised environment. This information can help adversaries determine which accounts exist, which can aid in follow-on behavior such as brute-forcing, spear-phishing attacks, or account takeovers (e.g., Valid Accounts).

Adversaries may use several methods to enumerate accounts, including abuse of existing tools, built-in commands, and potential misconfigurations that leak account names and roles or permissions in the targeted environment.

For examples, cloud environments typically provide easily accessible interfaces to obtain user lists. On hosts, adversaries can use default PowerShell and other command line functionality to identify accounts. Information about email addresses and accounts may also be extracted by searching an infected system’s files.

Positive Technologies products that cover the technique

MaxPatrol SIEM knowledge base

mssql_database: PT-CR-404: MSSQL_Administrator_List_Query: An attempt to get information about database users with administrator privileges mssql_database: PT-CR-554: MSSQL_Windows_Accounts_Discovery: An attempt to get information about the Windows groups and users using a stored procedure mssql_database: PT-CR-420: MSSQL_Self_Permissions_Discovery: An attempt to get information about the privileges of a current database user mssql_database: PT-CR-553: MSSQL_Db_Accounts_Discovery: An attempt to get information about the database level users mssql_database: PT-CR-422: MSSQL_Sql_Server_Users_Discovery: An attempt to get information about database users with SQL Server authentication pt_nad: PT-CR-734: NAD_Enumerate: PT NAD detected attempts to discover accounts it_bastion: PT-CR-2181: SKDPUNT_Collecting_Sessions_Info: Collection of session information of other users sap_attack_detection: PT-CR-151: SAPASABAP_Client_Bruteforce: Guessing of SAP client numbers bruteforce: PT-CR-906: LyncSmash_Use: Bruteforcing attempts for Skype accounts using LyncSmash active_directory_attacks: PT-CR-2550: LDAP_Discovery: A user executed a suspicious LDAP request that may indicate reconnaissance in the domain postgresql_database: PT-CR-1830: PostgreSQL_Users_Discovery: Execution of some SQL commands may indicate that information about the PostgreSQL database users is retrieved, which may indicate attacker activity

Subtechniques

Detection

ID	DS0009	Data source and component	Process: Process Creation	Description	Monitor for processes that can be used to enumerate user accounts and groups such as `net.exe` and `net1.exe`, especially when executed in quick succession. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.

ID	DS0017	Data source and component	Command: Command Execution	Description	Monitor logs and other sources of command execution history for actions that could be taken to gather information about accounts, including the use of calls to cloud APIs that perform account discovery. System and network discovery techniques normally occur throughout an operation as an adversary learns the environment, and also to an extent in normal network operations. Therefore discovery data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as Lateral Movement, based on the information obtained.

ID	DS0022	Data source and component	File: File Access	Description	Monitor access to file resources that contain local accounts and groups information such as `/etc/passwd`, `/Users` directories, and the SAM database. If access requires high privileges, look for non-admin objects (such as users or processes) attempting to access restricted file resources.

ID	Data source and component	Description
DS0009	Process: Process Creation	Monitor for processes that can be used to enumerate user accounts and groups such as `net.exe` and `net1.exe`, especially when executed in quick succession. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.
DS0017	Command: Command Execution	Monitor logs and other sources of command execution history for actions that could be taken to gather information about accounts, including the use of calls to cloud APIs that perform account discovery. System and network discovery techniques normally occur throughout an operation as an adversary learns the environment, and also to an extent in normal network operations. Therefore discovery data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as Lateral Movement, based on the information obtained.
DS0022	File: File Access	Monitor access to file resources that contain local accounts and groups information such as `/etc/passwd`, `/Users` directories, and the SAM database. If access requires high privileges, look for non-admin objects (such as users or processes) attempting to access restricted file resources.

Mitigation

ID	M1028	Name	Operating System Configuration	Description	Prevent administrator accounts from being enumerated when an application is elevating through UAC since it can lead to the disclosure of account names. The Registry key is located `HKLM\ SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\CredUI\EnumerateAdministrators`. It can be disabled through GPO: Computer Configuration > [Policies] > Administrative Templates > Windows Components > Credential User Interface: E numerate administrator accounts on elevation.

ID	M1018	Name	User Account Management	Description	Manage the creation, modification, use, and permissions associated to user accounts.

ID	Name	Description
M1028	Operating System Configuration	Prevent administrator accounts from being enumerated when an application is elevating through UAC since it can lead to the disclosure of account names. The Registry key is located `HKLM\ SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\CredUI\EnumerateAdministrators`. It can be disabled through GPO: Computer Configuration > [Policies] > Administrative Templates > Windows Components > Credential User Interface: E numerate administrator accounts on elevation.
M1018	User Account Management	Manage the creation, modification, use, and permissions associated to user accounts.