CAPEC-600 Credential Stuffing

An adversary tries known username/password combinations against different systems, applications, or services to gain additional authenticated access. Credential Stuffing attacks rely upon the fact that many users leverage the same username/password combination for multiple systems, applications, and services.

Attacks of this kind often target management services over commonly used ports such as SSH, FTP, Telnet, LDAP, Kerberos, MySQL, and more. Additional targets include Single Sign-On (SSO) or cloud-based applications/services that utilize federated authentication protocols, and externally facing applications. The primary goal of Credential Stuffing is to achieve lateral movement and gain authenticated access to additional systems, applications, and/or services. A successfully executed Credential Stuffing attack could result in the adversary impersonating the victim or executing any action that the victim is authorized to perform. Although not technically a brute force attack, Credential Stuffing attacks can function as such if an adversary possess multiple known passwords for the same user account. This may occur in the event where an adversary obtains user credentials from multiple sources or if the adversary obtains a user's password history for an account. Credential Stuffing attacks are similar to Password Spraying attacks (CAPEC-565) regarding their targets and their overall goals. However, Password Spraying attacks do not have any insight into known username/password combinations and instead leverage common or expected passwords. This also means that Password Spraying attacks must avoid inducing account lockouts, which is generally not a worry of Credential Stuffing attacks. Password Spraying attacks may additionally lead to Credential Stuffing attacks, once a successful username/password combination is discovered.

1. [Explore] [Acquire known credentials] The adversary must obtain known credentials in order to access the target system, application, or service. 2. [Explore] [Determine target's password policy] Determine the password policies of the target system/application to determine if the known credentials fit within the specified criteria. 3. [Experiment] [Attempt authentication] Try each username/password combination until the target grants access. 3. [Exploit] [Impersonate] An adversary can use successful experiments or authentications to impersonate an authorized user or system or to laterally move within a system or application 4. [Exploit] [Spoofing] Malicious data can be injected into the target system or into a victim user's system by an adversary. The adversary can also pose as a legitimate user to perform social engineering attacks. 5. [Exploit] [Data Exfiltration] The adversary can obtain sensitive data contained within the system or application.

• The system/application uses one factor password based authentication, SSO, and/or cloud-based authentication. • The system/application does not have a sound password policy that is being enforced. • The system/application does not implement an effective password throttling mechanism. • The adversary possesses a list of known user accounts and corresponding passwords that may exist on the target.

• [Low] A Credential Stuffing attack is very straightforward.

• Confidentiality, Access Control, Authentication: Gain Privileges • Confidentiality, Authorization: Read Data • Integrity: Modify Data

• Leverage multi-factor authentication for all authentication services and prior to granting an entity access to the domain network. • Create a strong password policy and ensure that your system enforces this policy. • Ensure users are not reusing username/password combinations for multiple systems, applications, or services. • Do not reuse local administrator account credentials across systems. • Deny remote use of local admin credentials to log into domain systems. • Do not allow accounts to be a local administrator on more than one system. • Implement an intelligent password throttling mechanism. Care must be taken to assure that these mechanisms do not excessively enable account lockout attacks such as CAPEC-2. • Monitor system and domain logs for abnormal credential access.