Query: indicators of Exploitation for Defense Impairment
Matching passage: T1687 Exploitation for Defense Impairment. Tactics: defense impairment. Description: Adversaries may exploit vulnerabilities in security software, infrastructure, or defensive components to degrade, disable, or otherwise continue to impair their ability to prevent, detect, or respond to malicious activity. Adversaries may exploit a system or application vulnerability to directly interfere with defensive mechanisms. Exploitation occurs when an adversary takes advantage of a programming error in software, services, or the operating system to execute adversary-controlled code, often with the goal of weakening or disabling protections. Vulnerabilities may exist in security tools such as antivirus, endpoint detection and response (EDR), firewalls, or other monitoring solutions. Adversaries may use prior reconnaissance or perform discovery activities (e.g., [Software Discovery](https://attack.mitre.org/techniques/T1518)) to identify defensive tools present in an environment and target them for exploitation. Successful exploitation may allow adversaries to terminate security processes, disable protections, bypass enforcement mechanisms, or reduce the effectiveness of defensive controls. In some cases, vulnerabilities in cloud-based or SaaS infrastructure may also be leveraged to bypass built-in security boundaries or disrupt visibility and enforcement across environments.(Citation: Salesforce zero-day in facebook phishing attack)
Near-miss passage: T1484.001 Group Policy Modification. Tactics: defense impairment, privilege escalation. Description: Adversaries may modify Group Policy Objects (GPOs) to subvert the intended discretionary access controls for a domain, usually with the intention of escalating privileges on the domain. Group policy allows for centralized management of user and computer settings in Active Directory (AD). GPOs are containers for group policy settings made up of files stored within a predictable network path `\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.(Citation: TechNet Group Policy Basics)(Citation: ADSecurity GPO Persistence 2016) Like other objects in AD, GPOs have access controls associated with them. By default all user accounts in the domain have permission to read GPOs. It is possible to delegate GPO access control permissions, e.g. write access, to specific users or groups in the domain. Malicious GPO modifications can be used to implement many other malicious behaviors such as [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053), [Disable or Modify Tools](https://attack.mitre.org/techniques/T1685), [Ingress Tool Transfer](https://attack.mitre.org/techniques/T1105), [Create Account](https://attack.mitre.org/techniques/T1136), [Service Execution](https://attack.mitre.org/techniques/T1569/002), and more.(Citation: ADSecurity GPO Persistence 2016)(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO Permissions)(Citation: Mandiant M Trends 2016)(Citation: Microsoft Hacking Team Breach) Since GPOs can control so many user and machine settings in the AD environment, there are a great number of potential attacks that can stem from this GPO abuse.(Citation: Wald0 Guide to GPOs) For example, publicly available scripts such as <code>New-GPOImmediateTask</code> can be leveraged to automate the creation of a malicious [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053) by modifying GPO settings, in this case modifying <code>&lt;GPO_PATH&gt;\Machine\Preferences\ScheduledTasks\ScheduledTasks.xml</code>.(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO P