Automating Response to Unauthorized User Privilege Escalations Using PowerShell Commands

Introduction

The Cortex XSIAM Response and Remediation Pack is designed to revolutionize incident response in modern security operations centers (SOCs). The playbooks empower analysts to focus on critical decision-making, rather than expending time on manual and repetitive tasks. This blog delves into the "User added to local administrator group using a PowerShell command" playbook, which automates response to such an analytics alert.

Threat Overview

Privilege escalation through unauthorized additions to the local administrator group is a significant security concern. Attackers frequently use PowerShell commands to achieve this, taking advantage of its versatility and integration into Windows. Such activities can grant adversaries elevated access, allowing them to move laterally within the network, exfiltrate data exfiltration, and maintain persistence.

Organizations must detect and address these threats swiftly to minimize the risk of potential damage. The ability to investigate the context of such activities and respond effectively ensures robust protection against privilege abuse.

Purpose of the Playbook

The "User added to local administrator group using a PowerShell command" playbook is designed to:

• Investigate alerts related to unauthorized privilege escalation.
• Determine the legitimacy of user additions to the local administrator group by examining alert context and process details.
• Enable automated and guided remediation actions to mitigate potential threats.

This playbook empowers SOC teams to address incidents swiftly, combining automation with human oversight to ensure thorough investigation and response.

Stages of the Playbook

The "User added to local administrator group using a PowerShell command" playbook progresses through these stages:

1. Investigation:
   • Collects and examines Cortex XSIAM alerts related to the host machine.
   • Evaluates whether processes associated with the alert are unsigned, which could indicate tampering or malicious activity.
   • MITRE Technique Analysis:
     • Searches for related alerts that align with MITRE tactics and techniques, including:
       1. T1001: Data Obfuscation
       2. T1140: Deobfuscate/Decode Files
       3. T1059: Command and Scripting Interpreter
     • Our research on our product shows that when these techniques are observed alongside “User added to local administrator group using a PowerShell command” alert, it strongly indicates that an attacker is the initiator of the action.

1. Remediation:
   • Terminates suspicious processes identified during the investigation using causality data.
   • Extracts the username of the account added to the local administrator group.
   • Requests analyst approval to remove the unauthorized user from the administrator group.
   • Fallback for Manual Actions:
     • If automated removal fails, provide step-by-step instructions for manual resolution.

Security Challenges Addressed

This playbook provides solutions to several critical security challenges:

• Proactive Detection: Quickly identifies unauthorized privilege escalations.
• Streamlined Investigation: Automates key steps while enabling analysts to make informed decisions.
• Efficient Remediation: Balances automation with manual intervention to ensure threats are effectively and quickly neutralized.

Conclusion

Privilege escalation is a critical security threat that requires immediate action. The "User added to local administrator group using a PowerShell command" playbook provides SOC teams with a robust, automated approach to detect, investigate, and remediate such incidents. By leveraging the Cortex XSIAM Response and Remediation Pack, organizations can bolster their defenses and ensure a proactive security posture.

Learn More

Explore the full capabilities of the Cortex XSIAM Response and Remediation Pack on the Cortex Marketplace: Cortex Response and Remediation Pack.