Trusted Design
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop.(Citation: volexity_0day_sophos_FW) 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.
In some cases, adversaries may abuse inactive accounts: for example, those belonging to individuals who are no longer part of an organization. Using these accounts may allow the adversary to evade detection, as the original account user will not be present to identify any anomalous activity taking place on their account.(Citation: CISA MFA PrintNightmare)
The overlap of permissions for local, domain, and cloud accounts 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.(Citation: TechNet Credential Theft)
T1078「Valid Accounts」（有効なアカウント） は、攻撃者がマルウェアなどの「ツール」ではなく、正規のユーザーから奪取した「認証情報」を使ってシステムに侵入・活動するテクニックです。
「脆弱性を突く」のではなく「正面玄関から鍵を使って入る」手法であるため、非常に検知が困難です。
攻撃者は、何らかの方法で入手した実在するユーザー名とパスワードを使用して、ターゲット環境内で活動します。
このテクニックは、攻撃の初期段階から最終段階まで幅広く使われます。
「鍵」を持たれている状態を想定した対策が必要です。
T1078自体は「盗んだパスワードを使う」という行為を指しますが、パスワードを盗むため、あるいは認証をバイパスするために以下のCVEが併用されることがあります。
この攻撃手法に関連する CVE は登録されていません。