| Summary |
An attacker gets access to the database table where hashes of passwords are stored. They then use a rainbow table of pre-computed hash chains to attempt to look up the original password. Once the original password corresponding to the hash is obtained, the attacker uses the original password to gain access to the system. A password rainbow table stores hash chains for various passwords. A password chain is computed, starting from the original password, P, via a reduce(compression) function R and a hash function H. A recurrence relation exists where Xi+1 = R(H(Xi)), X0 = P. Then the hash chain of length n for the original password P can be formed: X1, X2, X3, ... , Xn-2, Xn-1, Xn, H(Xn). P and H(Xn) are then stored together in the rainbow table. Constructing the rainbow tables takes a very long time and is computationally expensive. A separate table needs to be constructed for the various hash algorithms (e.g. SHA1, MD5, etc.). However, once a rainbow table is computed, it can be very effective in cracking the passwords that have been hashed without the use of salt. |
| Related CAPECS |
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CAPEC ID
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Description
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| CAPEC-49 |
In this attack, the adversary tries every possible value for a password until they succeed. A brute force attack, if feasible computationally, will always be successful because it will essentially go through all possible passwords given the alphabet used (lower case letters, upper case letters, numbers, symbols, etc.) and the maximum length of the password. A system will be particularly vulnerable to this type of an attack if it does not have a proper enforcement mechanism in place to ensure that passwords selected by users are strong passwords that comply with an adequate password policy. In practice a pure brute force attack on passwords is rarely used, unless the password is suspected to be weak. Other password cracking methods exist that are far more effective (e.g. dictionary attacks, rainbow tables, etc.). Knowing the password policy on the system can make a brute force attack more efficient. For instance, if the policy states that all passwords must be of a certain level, there is no need to check smaller candidates. |
| CAPEC-151 |
Identity Spoofing refers to the action of assuming (i.e., taking on) the identity of some other entity (human or non-human) and then using that identity to accomplish a goal. An adversary may craft messages that appear to come from a different principle or use stolen / spoofed authentication credentials. Alternatively, an adversary may intercept a message from a legitimate sender and attempt to make it look like the message comes from them without changing its content. The latter form of this attack can be used to hijack credentials from legitimate users. Identity Spoofing attacks need not be limited to transmitted messages - any resource that is associated with an identity (for example, a file with a signature) can be the target of an attack where the adversary attempts to change the apparent identity. This attack differs from Content Spoofing attacks where the adversary does not wish to change the apparent identity of the message but instead wishes to change what the message says. In an Identity Spoofing attack, the adversary is attempting to change the identity of the content. |
| CAPEC-560 |
An adversary guesses or obtains (i.e. steals or purchases) legitimate credentials (e.g. userID/password) to achieve authentication and to perform authorized actions under the guise of an authenticated user or service. Attacks leveraging trusted credentials typically result in the adversary laterally moving within the local network, since users are often allowed to login to systems/applications within the network using the same password. This further allows the adversary to obtain sensitive data, download/install malware on the system, pose as a legitimate user for social engineering purposes, and more.
Attacks on known passwords generally rely on the primary fact that users often reuse the same username/password combination for a variety of systems, applications, and services, coupled with poor password policies on the target system or application. Adversaries can also utilize known passwords to target Single Sign On (SSO) or cloud-based applications and services, which often don't verify the authenticity of the user's input. Known credentials are usually obtained by an adversary via a system/application breach and/or by purchasing dumps of credentials on the dark web. These credentials may be further gleaned via exposed configuration and properties files that contain system passwords, database connection strings, and other sensitive data.
Successful spoofing and impersonation of trusted credentials can lead to an adversary breaking authentication, authorization, and audit controls with the target system or application. |
| CAPEC-561 |
An adversary guesses or obtains (i.e. steals or purchases) legitimate Windows administrator credentials (e.g. userID/password) to access Windows Admin Shares on a local machine or within a Windows domain. Windows systems within the Windows NT family contain hidden network shares that are only accessible to system administrators. These shares allow administrators to remotely access all disk volumes on a network-connected system and further allow for files to be copied, written, and executed, along with other administrative actions. Example network shares include: C$, ADMIN$ and IPC$. If an adversary is able to obtain legitimate Windows credentials, the hidden shares can be accessed remotely, via server message block (SMB) or the Net utility, to transfer files and execute code. It is also possible for adversaries to utilize NTLM hashes to access administrator shares on systems with certain configuration and patch levels. |
| CAPEC-600 |
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. If the password obtained by the adversary is used for multiple systems, accounts, and/or services, this attack will be successful (in the absence of other mitigations).
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. |
| CAPEC-653 |
An adversary guesses or obtains (i.e. steals or purchases) legitimate Windows domain credentials (e.g. userID/password) to achieve authentication and to perform authorized actions on the domain, under the guise of an authenticated user or service. Attacks leveraging trusted Windows credentials typically result in the adversary laterally moving within the local Windows network, since users are often allowed to login to systems/applications within the domain using their Windows domain password. This domain authentication can occur directly (user typing in their password or PIN) or via Single Sign-On (SSO) or cloud-based authentication, which often don't verify the authenticity of the user's input. Known credentials are usually obtained by an adversary via a system/application breach and/or by purchasing dumps of credentials on the dark web. These credentials may be further gleaned via exposed configuration and properties files that contain system passwords, database connection strings, and other sensitive data. Utilizing known Windows credentials, an adversary can obtain sensitive data from administrator shares, download/install malware on the system, pose as a legitimate user for social engineering purposes, and more. Ultimately, successful spoofing and impersonation of trusted credentials can lead to an adversary breaking authentication, authorization, and audit controls with the target system or application. |
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