Adversaries may exploit software vulnerabilities in an attempt to elevate privileges. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Security constructs such as permission levels will often hinder access to information and use of certain techniques, so adversaries will likely need to perform privilege escalation to include use of software exploitation to circumvent those restrictions.
When initially gaining access to a system, an adversary may be operating within a lower privileged process which will prevent them from accessing certain resources on the system. Vulnerabilities may exist, usually in operating system components and software commonly running at higher permissions, that can be exploited to gain higher levels of access on the system. This could enable someone to move from unprivileged or user level permissions to SYSTEM or root permissions depending on the component that is vulnerable. This could also enable an adversary to move from a virtualized environment, such as within a virtual machine or container, onto the underlying host. This may be a necessary step for an adversary compromising an endpoint system that has been properly configured and limits other privilege escalation methods.
Adversaries may bring a signed vulnerable driver onto a compromised machine so that they can exploit the vulnerability to execute code in kernel mode. This process is sometimes referred to as Bring Your Own Vulnerable Driver (BYOVD).(Citation: ESET InvisiMole June 2020)(Citation: Unit42 AcidBox June 2020) Adversaries may include the vulnerable driver with files delivered during Initial Access or download it to a compromised system via Ingress Tool Transfer or Lateral Tool Transfer.
以下は、MITRE ATT&CKの T1068: Exploitation for Privilege Escalation(権限昇格のための脆弱性悪用) の整理です。
T1068は、ソフトウェアやOSの脆弱性を悪用して権限を昇格させる攻撃手法です。
攻撃者はこの手法により、例えば以下を実現できます:
つまり、「侵入後に“完全支配”へ進むための重要ステップ」です。 初期侵入だけでは制限されるため、より高権限を得るために使われます。
典型的な流れは以下の通りです:
例:
カーネル脆弱性
特に「既知の脆弱ドライバを持ち込む(BYOVD)」は近年増加傾向です。
主な対策は「脆弱性対策+振る舞い検知」です。
/proc やメモリ領域への不審アクセス検知「パッチ管理」と「Exploit対策製品」が特に重要です。
この技術の本質は以下です:
また、以下も重要です:
単体ではなく他の攻撃と組み合わせる
Initial Access → T1068 → 横展開
T1068に関連する典型的なCWEは以下です。特に「メモリ破壊系」と「アクセス制御不備」が多いです。
MITREでも実際の攻撃事例として多数挙げられています。これらはすべて「低権限 → SYSTEM/root」を可能にする脆弱性です。
T1068は一言でいうと:
「侵入後に“完全支配”へ到達するための鍵」
この攻撃手法を利用する脅威アクターは登録されていません。
この攻撃手法に関連する CVE は登録されていません。