T1211 - Exploitation for Defense Evasion

Adversaries may exploit a system or application vulnerability to bypass security features. Exploitation of a 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. Vulnerabilities may exist in defensive security software that can be used to disable or circumvent them.

Adversaries may have prior knowledge through reconnaissance that security software exists within an environment or they may perform checks during or shortly after the system is compromised for Security Software Discovery. The security software will likely be targeted directly for exploitation. There are examples of antivirus software being targeted by persistent threat groups to avoid detection.

There have also been examples of vulnerabilities in public cloud infrastructure of SaaS applications that may bypass defense boundaries (Citation: Salesforce zero-day in facebook phishing attack), evade security logs (Citation: Bypassing CloudTrail in AWS Service Catalog), or deploy hidden infrastructure.(Citation: GhostToken GCP flaw)

Atomic Tests:

Currently, no tests are available for this technique.

Detection

Exploitation for defense evasion may happen shortly after the system has been compromised to prevent detection during later actions for for additional tools that may be brought in and used. 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 system that might indicate successful compromise, such as abnormal behavior of processes. This could include suspicious files written to disk, evidence of Process Injection for attempts to hide execution or evidence of Discovery.

Shield Active Defense

Application Diversity

Present the adversary with a variety of installed applications and services.

Application diversity is presenting multiple software targets to the adversary. On a single target system, defenders can configure multiple different services or user software applications. On a target network, defenders can present systems with a variety of operating systems, operating system versions, applications, and services.

Opportunity

There is an opportunity to provide a variety of applications to an adversary to see what things an adversary prefers or to influence their operations.

Use Case

A defender can stand up decoy systems or processes using a wide array of applications. These applications can be hardened to test an adversary’s capabilities, or easily exploited to entice an adversary to move in that direction.

Procedures

Use a mix of vulnerable and nonvulnerable software on a system to allow you to see what exploits the adversary leverages in their attacks. Install Anti-virus or other end-point detection tools on systems to see if an adversary takes note of them and if so, how they react.