Valid Accounts

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Valid Accounts
Technique
ID T1078
Tactic Defense Evasion, Persistence, Privilege Escalation
Platform Windows Server 2003, Windows Server 2008, Windows Server 2012, Windows XP, Windows 7, Windows 8, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012 R2, Windows Vista, Windows 8.1, Linux, Windows 10, MacOS, OS X
Permissions Required User, Administrator
Effective Permissions User, Administrator
Data Sources Authentication logs, Process monitoring
Defense Bypassed Anti-virus, Firewall, Host intrusion prevention systems, Network intrusion detection system, Process whitelisting, System access controls
CAPEC ID CAPEC-560

Adversaries may steal the credentials of a specific user or service account using Credential Access techniques. Compromised credentials may be used to bypass access controls placed on various resources on hosts and within the network and may even be used for persistent access to remote systems. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Adversaries may also create accounts, sometimes using pre-defined account names and passwords, as a means for persistence through backup access in case other means are unsuccessful.

The overlap of credentials and permissions across a network of systems is of concern because the adversary may be able to pivot across accounts and systems to reach a high level of access (i.e., domain or enterprise administrator) to bypass access controls set within the enterprise.1

Examples

  • APT18 actors leverage legitimate credentials to log into external remote services.2
  • APT28 has used legitimate credentials to maintain access to a victim network and exfiltrate data.3
  • APT32 has used legitimate local admin account credentials.4
  • Carbanak actors used legitimate credentials of banking employees to perform operations that sent them millions of dollars.5
  • FIN10 has used stolen credentials to connect remotely to victim networks using VPNs protected with only a single factor. The group has also moved laterally using the Local Administrator account.6
  • To move laterally on a victim network, FIN6 has used credentials stolen from various systems on which it gathered usernames and password hashes.7
  • PittyTiger attempts to obtain legitimate credentials during operations.8
  • Suckfly used legitimate account credentials that they dumped to navigate the internal victim network as though they were the legitimate account owner.9
  • Threat Group-1314 actors used compromised credentials for the victim's endpoint management platform, Altiris, to move laterally.10
  • Threat Group-3390 actors obtain legitimate credentials using a variety of methods and use them to further lateral movement on victim networks.11
  • Threat Group-3390 has used OWA account credentials to attempt to regain access to a victim network after eviction.12
  • menuPass has used valid accounts shared between Managed Service Providers and clients to move between the two environments.13
  • Cobalt Strike can use known credentials to run commands and spawn processes as another user.14
  • Adversaries can instruct Duqu to spread laterally by copying itself to shares it has enumerated and for which it has obtained legitimate credentials (via keylogging or other means). The remote host is then infected by using the compromised credentials to schedule a task on remote machines that executes the malware.15
  • Some SeaDuke samples have a module to extract email from Microsoft Exchange servers using compromised credentials.16
  • If Shamoon cannot access shares using current privileges, it attempts access using hard coded, domain-specific credentials gathered earlier in the intrusion.17

Mitigation

Take measures to detect or prevent techniques such as Credential Dumping or installation of keyloggers to acquire credentials through Input Capture. Limit credential overlap across systems to prevent access if account credentials are obtained. Ensure that local administrator accounts have complex, unique passwords across all systems on the network. Do not put user or admin domain accounts in the local administrator groups across systems unless they are tightly controlled and use of accounts is segmented, as this is often equivalent to having a local administrator account with the same password on all systems. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers.18. Audit domain and local accounts as well as their permission levels routinely to look for situations that could allow an adversary to gain wide access by obtaining credentials of a privileged account.119

Detection

Configure robust, consistent account activity audit policies across the enterprise.20 Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts. Examples: one account logged into multiple systems simultaneously; multiple accounts logged into the same machine simultaneously; accounts logged in at odd times or outside of business hours. Activity may be from interactive login sessions or process ownership from accounts being used to execute binaries on a remote system as a particular account. Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).

Perform regular audits of domain and local system accounts to detect accounts that may have been created by an adversary for persistence.

References