Unleashing the Power of Threat Hunting for LockBit Ransomware

As cyber threats continue to evolve, organizations must proactively defend their networks against ransomware attacks like LockBit, which have proven to be highly destructive and financially crippling. Threat hunting has emerged as a critical practice that enables cybersecurity professionals to take a more offensive approach to identify and neutralize potential threats before they cause irreparable damage. In this blog, we will explore threat hunting for LockBit ransomware, including real-world examples, Splunk queries, and YARA rules to help organizations safeguard their assets and protect against this insidious malware.

LockBit is a notorious type of ransomware that encrypts victims’ files, rendering them inaccessible until a ransom is paid. Its operators employ sophisticated techniques, such as double extortion, where stolen data is threatened to be leaked if the ransom is not paid. LockBit spreads via phishing emails, exploit kits, and unpatched vulnerabilities, making it essential to be proactive in detecting and preventing its entry into the network.

Let’s look at some practical threat hunting examples to detect and respond to LockBit ransomware:

Example 1: Unusual File Access Pattern
Use Splunk to monitor file access patterns and detect sudden spikes in file modifications across the network.
Query:

index=main sourcetype=”access_logs” (status=200 OR status=204) earliest=-2d | stats count by clientip uri

Look for abnormal access patterns, such as multiple file changes within a short time period.

Example 2: Remote Desktop Protocol (RDP) Anomalies
Monitor RDP logs for suspicious activity and unauthorized access attempts.
Query:

index=windows sourcetype=”WinEventLog:Security” EventCode=4624 earliest=-1d | search Account_Name=”*” AND “Failure Information: Reason: Unknown user name or bad password”

Investigate failed login attempts and any access from unusual IP addresses.

YARA is a powerful tool used to create custom rules for detecting malware and suspicious files. Let’s create a YARA rule to identify LockBit ransomware:

rule LockBit_Ransomware {
meta:
description = “Detects LockBit ransomware files”
strings:
$magic = { 4D 5A } // MZ (DOS/Windows executable)
$pattern1 = “LockBit”
$pattern2 = “LOCKBIT” // Case-insensitive
condition:
$magic at 0 and ($pattern1 or $pattern2)
}

Leverage Splunk for network activity monitoring to detect potential LockBit infections:

index=network earliest=-1w
| rex field=_raw “Host=(?<dest_host>[^\s]+)”
| rex field=_raw “User_Agent=(?<user_agent>[^\s]+)”
| search dest_host=”*.onion” OR user_agent=”LockBit” OR user_agent=”LOCKBIT”

Threat hunting is an indispensable practice for organizations seeking to stay ahead of advanced ransomware like LockBit. By employing Splunk queries and YARA rules, cybersecurity teams can identify suspicious activities, detect potential threats, and respond swiftly to mitigate any damage caused. It is crucial to stay proactive and continuously evolve threat hunting techniques to defend against evolving cyber threats effectively. Implementing these strategies will strengthen your organization’s security posture, ensuring a resilient defense against the looming threat of LockBit and other ransomware variants. Remember, the best defense is a well-prepared offense. Happy hunting!

(Note: The examples provided in this blog are intended for illustrative purposes only and may require customization based on the specific environment and requirements of individual organizations.)