T1110: Brute Force
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained. Without knowledge of the password for an account or set of accounts, an adversary may systematically guess the password using a repetitive or iterative mechanism. Brute forcing passwords can take place via interaction with a service that will check the validity of those credentials or offline against previously acquired credential data, such as password hashes.
Brute forcing credentials may take place at various points during a breach. For example, adversaries may attempt to brute force access to Valid Accounts within a victim environment leveraging knowledge gathered from other post-compromise behaviors such as OS Credential Dumping, Account Discovery, or Password Policy Discovery. Adversaries may also combine brute forcing activity with behaviors such as External Remote Services as part of Initial Access.
If an adversary guesses the correct password but fails to login to a compromised account due to location-based conditional access policies, they may change their infrastructure until they match the victim’s location and therefore bypass those policies.
How it's found
Brute Force Authentication Failures with Multi-Platform Log Correlation: High volume of failed logon attempts followed by a successful one from a suspicious user, host, or timeframe Multiple authentication failures for valid or invalid users followed by success from same IP/user Password spraying or brute force attempts across user pool within short time intervals Multiple failed authentications in unified logs (e.g., loginwindow or sshd) Excessive login attempts followed by success from SaaS apps like O365, Dropbox, etc.
Sub-techniques
T1110.001: Password Guessing
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts. Without knowledge of the password for an account, an adversary may opt to systematically guess the password using a repetitive or iterative mechanism. An adversary may guess login credentials without prior knowledge of system or environment passwords during an operation by using a list of common passwords. Password guessing may or may not take into account the target's policies on password complexity or use policies that may lock accounts out after a number of failed attempts. Guessing passwords can be a risky option because it could cause numerous authentication failures and account lockouts, depending on the organization's login failure policies. Typically, management services over commonly used ports are used when guessing passwords. Commonly targeted services include the following: * SSH (22/TCP) * Telnet (23/TCP) * FTP (21/TCP) * NetBIOS / SMB / Samba (139/TCP & 445/TCP) * LDAP (389/TCP) * Kerberos (88/TCP) * RDP / Terminal Services (3389/TCP) * HTTP/HTTP Management Services (80/TCP & 443/TCP) * MSSQL (1433/TCP) * Oracle (1521/TCP) * MySQL (3306/TCP) * VNC (5900/TCP) * SNMP (161/UDP and 162/TCP/UDP) In addition to management services, adversaries may "target single sign-on (SSO) and cloud-based applications utilizing federated authentication protocols," as well as externally facing email applications, such as Office 365.. Further, adversaries may abuse network device interfaces (such as `wlanAPI`) to brute force accessible wifi-router(s) via wireless authentication protocols. In default environments, LDAP and Kerberos connection attempts are less likely to trigger events over SMB, which creates Windows "logon failure" event ID 4625.
T1110.002: Password Cracking
Adversaries may use password cracking to attempt to recover usable credentials, such as plaintext passwords, when credential material such as password hashes are obtained. OS Credential Dumping can be used to obtain password hashes, this may only get an adversary so far when Pass the Hash is not an option. Further, adversaries may leverage Data from Configuration Repository in order to obtain hashed credentials for network devices. Techniques to systematically guess the passwords used to compute hashes are available, or the adversary may use a pre-computed rainbow table to crack hashes. Cracking hashes is usually done on adversary-controlled systems outside of the target network. The resulting plaintext password resulting from a successfully cracked hash may be used to log into systems, resources, and services in which the account has access.
T1110.003: Password Spraying
Adversaries may use a single or small list of commonly used passwords against many different accounts to attempt to acquire valid account credentials. Password spraying uses one password (e.g. 'Password01'), or a small list of commonly used passwords, that may match the complexity policy of the domain. Logins are attempted with that password against many different accounts on a network to avoid account lockouts that would normally occur when brute forcing a single account with many passwords. Typically, management services over commonly used ports are used when password spraying. Commonly targeted services include the following: * SSH (22/TCP) * Telnet (23/TCP) * FTP (21/TCP) * NetBIOS / SMB / Samba (139/TCP & 445/TCP) * LDAP (389/TCP) * Kerberos (88/TCP) * RDP / Terminal Services (3389/TCP) * HTTP/HTTP Management Services (80/TCP & 443/TCP) * MSSQL (1433/TCP) * Oracle (1521/TCP) * MySQL (3306/TCP) * VNC (5900/TCP) In addition to management services, adversaries may "target single sign-on (SSO) and cloud-based applications utilizing federated authentication protocols," as well as externally facing email applications, such as Office 365. In order to avoid detection thresholds, adversaries may deliberately throttle password spraying attempts to avoid triggering security alerting. Additionally, adversaries may leverage LDAP and Kerberos authentication attempts, which are less likely to trigger high-visibility events such as Windows "logon failure" event ID 4625 that is commonly triggered by failed SMB connection attempts.
T1110.004: Credential Stuffing
Adversaries may use credentials obtained from breach dumps of unrelated accounts to gain access to target accounts through credential overlap. Occasionally, large numbers of username and password pairs are dumped online when a website or service is compromised and the user account credentials accessed. The information may be useful to an adversary attempting to compromise accounts by taking advantage of the tendency for users to use the same passwords across personal and business accounts. Credential stuffing is a risky option because it could cause numerous authentication failures and account lockouts, depending on the organization's login failure policies. Typically, management services over commonly used ports are used when stuffing credentials. Commonly targeted services include the following: * SSH (22/TCP) * Telnet (23/TCP) * FTP (21/TCP) * NetBIOS / SMB / Samba (139/TCP & 445/TCP) * LDAP (389/TCP) * Kerberos (88/TCP) * RDP / Terminal Services (3389/TCP) * HTTP/HTTP Management Services (80/TCP & 443/TCP) * MSSQL (1433/TCP) * Oracle (1521/TCP) * MySQL (3306/TCP) * VNC (5900/TCP) In addition to management services, adversaries may "target single sign-on (SSO) and cloud-based applications utilizing federated authentication protocols," as well as externally facing email applications, such as Office 365.
Standards mapping
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is T1110 Brute Force?
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained. Without knowledge of the password for an account or set of accounts, an adversary may systematically guess the password using a repetitive or iterative mechanism. Brute forcing passwords can take place via interaction with a service that will check the validity of those credentials or offline against previously acquired credential data, such as password hashes. Brute forcing credentials may take place at various points during a breach. For example, adversaries may attempt to brute force access to Valid Accounts within a victim environment leveraging knowledge gathered from other post-compromise behaviors such as OS Credential Dumping, Account Discovery, or Password Policy Discovery. Adversaries may also combine brute forcing activity with behaviors such as External Remote Services as part of Initial Access. If an adversary guesses the correct password but fails to login to a compromised account due to location-based conditional access policies, they may change their infrastructure until they match the victim’s location and therefore bypass those policies.
Which tactics does T1110 belong to?
T1110 maps to the Credential Access tactic.
Does TurboPentest test for Brute Force?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related MITRE ATT&CK techniques
- Credential AccessT1003: OS Credential Dumping
- Credential Access, DiscoveryT1040: Network Sniffing
- Credential Access, CollectionT1056: Input Capture
- Credential AccessT1111: Multi-Factor Authentication Interception
- Credential AccessT1187: Forced Authentication
- Credential AccessT1212: Exploitation for Credential Access
About this reference
These security references are maintained by IntegSec, an offensive-security firm whose team holds CISSP, OSCP, and OSCE certifications and has run thousands of penetration tests. Content is kept current as tools, standards, and attack techniques evolve.
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