CyberDefenders — LockBit Lab Writeup

📰 Medium · Cybersecurity

Learn how to investigate and mitigate a multi-stage ransomware attack targeting a corporate network, starting with a compromised Microsoft SQL Server.

intermediate Published 18 Apr 2026

Action Steps

Investigate the initial compromise of a Microsoft SQL Server using a brute-force attack on the `sa` account
Analyze the escalation of privileges by enabling the `xp_cmdshell` configuration to execute system-level commands
Identify the disabling of security defenses, such as Windows Defender, across the domain via PowerShell and remote registry modifications
Detect credential dumping (LSASS access) and the establishment of persistence via scheduled tasks
Apply mitigation strategies to prevent lateral movement across the network

Who Needs to Know This

Security teams and incident responders can benefit from understanding the tactics, techniques, and procedures (TTPs) used by threat actors in ransomware attacks, and apply this knowledge to improve their defensive strategies.

Key Insight

💡 Ransomware attacks often involve a combination of brute-force attacks, privilege escalation, and security defense evasion, making it essential to implement robust security measures and monitor for suspicious activity.

Key Takeaways

Learn how to investigate and mitigate a multi-stage ransomware attack targeting a corporate network, starting with a compromised Microsoft SQL Server.

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Title: CyberDefenders — LockBit Lab Writeup

URL Source: https://medium.com/@JBXSec/cyberdefenders-lockbit-lab-writeup-743d9ba9065b?source=rss------cybersecurity-5

Published Time: 2026-04-18T22:56:52Z

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# CyberDefenders — LockBit Lab Writeup | by JBXSec | Apr, 2026 | Medium

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# CyberDefenders — LockBit Lab Writeup

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## Overview

The CyberDefenders: LockBit Lab investigation explores a multi-stage ransomware attack targeting a corporate network, beginning with the compromise of a Microsoft SQL Server. The threat actor gained entry through a brute-force attack on the `sa` account, subsequently escalating privileges by enabling the `xp_cmdshell` configuration to execute system-level commands. From this initial foothold, the attacker systematically disabled security defenses, specifically Windows Defender across the domain via PowerShell and remote registry modifications. The intrusion progressed through credential dumping (LSASS access) and the establishment of persistence via scheduled tasks, ultimately facilitating lateral movement across the network.

## Scenario

A medium-sized corporation has experienced a ransomware attack, first identified when a user reported a ransom note on their screen alongside a Windows Defender al

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CyberDefenders — LockBit Lab Writeup

Key Takeaways

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