T1068 Exploitation for Privilege Escalation

High-Level Description

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). 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.

Kill Chain Phase

• Privilege Escalation (TA0004)

Platforms: Containers, Linux, macOS, Windows

What to Check

• ] Identify if Exploitation for Privilege Escalation technique is applicable to target environment
• ] Check Containers systems for indicators of Exploitation for Privilege Escalation
• ] Check Linux systems for indicators of Exploitation for Privilege Escalation
• ] Check macOS systems for indicators of Exploitation for Privilege Escalation
• ] Verify mitigations are bypassed or absent (5 known mitigations)
• ] Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

1. Identify Attack Surface: Determine if the target environment is susceptible to Exploitation for Privilege Escalation by examining the target platforms (Containers, Linux, macOS).

1. Assess Existing Defenses: Review whether mitigations for T1068 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

1. Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.

> Note: No Atomic Red Team tests available for this technique. See Atomic Red Team GitHub for updates.

Remediation Guide

M1051 Update Software

Update software regularly by employing patch management for internal enterprise endpoints and servers.

M1050 Exploit Protection

Security applications that look for behavior used during exploitation such as Windows Defender Exploit Guard (WDEG) and the Enhanced Mitigation Experience Toolkit (EMET) can be used to mitigate some exploitation behavior. Control flow integrity checking is another way to potentially identify and stop a software exploit from occurring. Many of these protections depend on the architecture and target application binary for compatibility and may not work for software components targeted for privilege escalation.

M1048 Application Isolation and Sandboxing

Make it difficult for adversaries to advance their operation through exploitation of undiscovered or unpatched vulnerabilities by using sandboxing. Other types of virtualization and application microsegmentation may also mitigate the impact of some types of exploitation. Risks of additional exploits and weaknesses in these systems may still exist.

M1019 Threat Intelligence Program

Develop a robust cyber threat intelligence capability to determine what types and levels of threat may use software exploits and 0-days against a particular organization.

M1038 Execution Prevention

Consider blocking the execution of known vulnerable drivers that adversaries may exploit to execute code in kernel mode. Validate driver block rules in audit mode to ensure stability prior to production deployment.

Detection

Detection Strategy for Exploitation for Privilege Escalation

Risk Assessment

| Finding | Severity | Impact | | ---------------------------------------------------------- | -------- | -------------------- | | Exploitation for Privilege Escalation technique applicable | High | Privilege Escalation |

CWE Categories

| CWE ID | Title | | ------- | ----------------------------- | | CWE-269 | Improper Privilege Management |

References

• ESET InvisiMole June 2020
• Microsoft Driver Block Rules
• Unit42 AcidBox June 2020
• Atomic Red Team - T1068
• MITRE ATT&CK - T1068