interlock-ransomware

Interlock Ransomware: How ClickFix Bypasses Security Defenses

Today in Tech

04 Aug 2025 — 3 min read

Callback Phishing Attack Tactics Evolved - Drops Ransomware

Interlock Ransomware: How ClickFix Bypasses Security Defenses

A new ransomware threat called Interlock is making waves in the cybersecurity world, not just for its double extortion tactics, but also for its innovative use of social engineering. This ransomware employs a technique called ClickFix to gain initial access to systems, bypassing many traditional security defenses. Let's dive into what makes Interlock and ClickFix so dangerous and what you can do to protect your organization.

Callback Phishing Attack Tactics Evolved - Drops Ransomware

What is Interlock Ransomware?

Interlock is a ransomware group that has been actively targeting businesses and critical infrastructure since 2024. What sets Interlock apart is its use of less common initial access methods, including drive-by downloads from compromised websites and a social engineering tactic known as ClickFix. This ransomware is known for double extortion, meaning it not only encrypts your data but also threatens to leak it publicly if the ransom is not paid.

The ClickFix Technique Explained

ClickFix is a social engineering technique used by Interlock to trick users into executing malicious PowerShell commands. Here's how it typically works:

Victims are redirected to compromised websites, often through drive-by downloads.
On these websites, users are presented with fake CAPTCHAs or system alert prompts.
These prompts coax users into copying and pasting a seemingly harmless command into their PowerShell console.
Unbeknownst to the user, the command is actually a malicious payload that initiates the ransomware infection.

This technique is particularly effective because it relies on user interaction, bypassing many automated security measures that would typically block malicious scripts.

Targets and Impact

Interlock has been observed targeting a range of industries, with a particular focus on critical infrastructure, including healthcare. The impact of an Interlock ransomware attack can be devastating, leading to:

Data encryption and loss
Operational disruption
Financial losses due to ransom demands and recovery costs
Reputational damage

How to Protect Your Organization

Protecting against Interlock and similar ransomware threats requires a multi-layered approach:

Employee Training: Educate employees about social engineering tactics like ClickFix and the importance of verifying the legitimacy of websites and prompts before interacting with them.
Security Awareness: Promote a culture of security awareness where employees are encouraged to report suspicious activity.
Endpoint Protection: Implement robust endpoint protection solutions that can detect and block malicious scripts and executables.
Regular Backups: Maintain regular backups of critical data to ensure business continuity in the event of a ransomware attack.
Vulnerability Management: Regularly scan for and patch vulnerabilities in your systems and applications.
Network Segmentation: Segment your network to limit the lateral movement of ransomware in case of a breach.

Key Takeaways

Interlock ransomware's ClickFix technique highlights the importance of user awareness and a layered security approach. By understanding how these attacks work and implementing appropriate security measures, organizations can significantly reduce their risk of falling victim to Interlock and other sophisticated ransomware threats.