T1068 - Exploitation for Privilege Escalation

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.

Atomic Tests:

Currently, no tests are available for this technique.

Detection

Detecting software exploitation may be difficult depending on the tools available. Software exploits may not always succeed or may cause the exploited process to become unstable or crash. Also look for behavior on the endpoint system that might indicate successful compromise, such as abnormal behavior of the processes. This could include suspicious files written to disk, evidence of Process Injection for attempts to hide execution or evidence of Discovery. Consider monitoring for the presence or loading (ex: Sysmon Event ID 6) of known vulnerable drivers that adversaries may drop and exploit to execute code in kernel mode.(Citation: Microsoft Driver Block Rules)

Higher privileges are often necessary to perform additional actions such as some methods of OS Credential Dumping. Look for additional activity that may indicate an adversary has gained higher privileges.

Shield Active Defense

Admin Access

Modify a user’s administrative privileges.

Changing the target system to allow or disallow users to perform tasks requiring administrator level permissions gives the defender leverage in inhibiting or facilitating attacks. The procedures for changing these permissions vary across different operating and software systems.

Opportunity

There is an opportunity to study the adversary and collect first-hand observations about them and their tools.

Use Case

A defender can configure system users to not have admin access in order to ensure privilege escalation requires exploitation.

Procedures

Remove an account’s administrative access from a system or service to require an adversary to reveal techniques for elevating privileges in order to accomplish certain tasks. Grant an account administrative access to a system or service to enable an adversary to take advantage of those privileges if they compromise the system or service.