Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software. Credentials can then be used to perform Lateral Movement and access restricted information.
Gathering Windows cred Hashes from the Network
PinchDuke steals credentials from compromised hosts. PinchDuke's credential stealing functionality is believed to be based on the source code of the Pinch credential stealing malware (also known as LdPinch). Credentials targeted by PinchDuke include ones associated many sources such as WinInet Credential Cache, and Lightweight Directory Access Protocol (LDAP).[11]
Monitor executed commands and arguments that may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software. Look for command-lines that invoke AuditD or the Security Accounts Manager (SAM). Remote access tools may contain built-in features or incorporate existing tools like Mimikatz. PowerShell scripts also exist that contain credential dumping functionality, such as PowerSploit's Invoke-Mimikatz module, [33] which may require additional logging features to be configured in the operating system to collect necessary information for analysis.
Monitor for API calls that may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software.
Monitor for the SAM registry key being accessed that may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software.
Mimikatz has a feature (dcsync) which utilises the Directory Replication Service (DRS) to retrieve the password hashes from the NTDS.DIT file. This technique eliminates the need to authenticate directly with the domain controller as it can be executed from any system that is part of the domain from the context of domain administrator. Therefore it is the standard technique for red teams as it is less noisy.
PowerShell Empire has two modules which can retrieve domain hashes via the DCSync attack. Both modules needs to be executed from the perspective of domain administrator and they are using Microsoft replication services. These modules rely on the Invoke-Mimikatz PowerShell script in order to execute Mimikatz commands related to DCSync. The following module will extract the domain hashes to a format similar to the output of Metasploit hashdump command.
The ntdsutil is a command line tool that is part of the domain controller ecosystem and its purpose is to enable administrators to access and manage the windows Active Directory database. However it can be abused by penetration testers and red teams to take a snapshot of the existing ntds.dit file which can be copied into a new location for offline analysis and extraction of password hashes.
Windows credentials management is the process by which the operating system receives the credentials from the service or user and secures that information for future presentation to the authenticating target. In the case of a domain-joined computer, the authenticating target is the domain controller. The credentials used in authentication are digital documents that associate the user's identity to some form of proof of authenticity, such as a certificate, a password, or a PIN.
Packaging credentials for interactive and network logon includes the process of serialization. By serializing credentials multiple logon tiles can be displayed on the logon UI. Therefore, your organization can control the logon display such as users, target systems for logon, pre-logon access to the network and workstation lock/unlock policies - through the use of customized credential providers. Multiple credential providers can co-exist on the same computer.
Each version of Windows contains one default credential provider and one default Pre-Logon-Access Provider (PLAP), also known as the SSO provider. The SSO provider permits users to make a connection to a network before logging on to the local computer. When this provider is implemented, the provider does not enumerate tiles on Logon UI.
Multiple network authentications are followed by one of the other scenarios. For example, a user authenticates to an Internet service provider (ISP), authenticates to a VPN, and then uses their user account credentials to log on locally.
Network authentication and computer logon are handled by the same credential provider. In this scenario, the user is required to connect to the network before logging on to the computer.
Before starting a service, the service controller logs on by using the account that is designated for the service, and then presents the service's credentials for authentication by the LSA. The Windows service implements a programmatic interface that the service controller manager can use to control the service. A Windows service can be started automatically when the system is started or manually with a service control program. For example, when a Windows client computer joins a domain, the messenger service on the computer connects to a domain controller and opens a secure channel to it. To obtain an authenticated connection, the service must have credentials that the remote computer's Local Security Authority (LSA) trusts. When communicating with other computers in the network, LSA uses the credentials for the local computer's domain account, as do all other services running in the security context of the Local System and Network Service. Services on the local computer run as SYSTEM so credentials do not need to be presented to the LSA.
The Local Security Authority Subsystem Service (LSASS) stores credentials in memory on behalf of users with active Windows sessions. The stored credentials let users seamlessly access network resources, such as file shares, Exchange Server mailboxes, and SharePoint sites, without re-entering their credentials for each remote service.
Validation mechanisms rely on the presentation of credentials at the time of logon. However, when the computer is disconnected from a domain controller, and the user is presenting domain credentials, Windows uses the process of cached credentials in the validation mechanism.
Introduced in Windows Server 2012 R2 and Windows 8.1, Restricted Admin mode provides additional security to remote logon scenarios. This mode of Remote Desktop causes the client application to perform a network logon challenge-response with the NT one-way function (NTOWF) or use a Kerberos service ticket when authenticating to the remote host. After the administrator is authenticated, the administrator does not have the respective account credentials in LSASS because they were not supplied to the remote host. Instead, the administrator has the computer account credentials for the session. Administrator credentials are not supplied to the remote host, so actions are performed as the computer account. Resources are also limited to the computer account, and the administrator cannot access resources with his own account.
These credentials become an encrypted part of a user's local profile in the \Documents and Settings\Username\Application Data\Microsoft\Credentials directory. As a result, these credentials can roam with the user if the user's network policy supports Roaming User Profiles. However, if the user has copies of Stored User Names and Passwords on two different computers and changes the credentials that are associated with the resource on one of these computers, the change is not propagated to Stored User Names and Passwords on the second computer.
Credential management by using Credential Manager is controlled by the user on the local computer. Users can save and store credentials from supported browsers and Windows applications to make it convenient when they need to sign in to these resources. Credentials are saved in special encrypted folders on the computer under the user's profile. Applications that support this feature (through the use of the Credential Manager APIs), such as web browsers and apps, can present the correct credentials to other computers and websites during the logon process.
For example, client computers running a Windows operating system participate in a network domain by communicating with a domain controller even when no human user is logged on. To initiate communications, the computer must have an active account in the domain. Before accepting communications from the computer, the LSA on the domain controller authenticates the computer's identity and then constructs the computer's security context just as it does for a human security principal. This security context defines the identity and capabilities of a user or service on a particular computer or a user, service, or computer on a network. For example, the access token contained within the security context defines the resources (such as a file share or printer) that can be accessed and the actions (such as Read, Write, or Modify) that can be performed by that principal - a user, computer, or service on that resource.
The security context of a user or computer can vary from one computer to another, such as when a user logs on to a server or a workstation other than the user's own primary workstation. It can also vary from one session to another, such as when an administrator modifies the user's rights and permissions. In addition, the security context is usually different when a user or computer is operating on a stand-alone basis, in a network, or as part of an Active Directory domain.
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