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What Is the Blister Malware? Tips to Stay Protected

Are you tired of random pop-ups, sluggish laptops, computer viruses, or the threat of ransomware attacks? No matter which shape or form malware takes, it’s annoying and can even be devastating.

And sometimes, you don’t even know you’re a victim until it’s too late. That’s the case with Blister malware, a particularly stealthy example of malicious software.

So, what exactly is the Blister malware, and what does it do? And are there any ways to protect against malware?

What Is the Blister Malware?

Discovered by Elastic Security, Blister malware is an evasive malware campaign that takes advantage of valid code signing certificates to tiptoe past security defenses such as anti-viruses, and, in doing so, manages to avoid detection.

Named after one of its payloads called Blister—which is well-known for deploying second-stage payloads—the main aim of this malware is to deploy Cobalt Strike and BitRAT payloads on compromised systems.

Related: What Is Malware and How Does It Work?

How Does the Blister Malware Execute?

Blister malware rears its ugly head by dropping and executing another malware or by injecting its payload.

Cybercriminals sometimes use code-signing to evade detection and bypass security checks with ease. The Blister malware employs this same tactic and uses a Sectigo issued certificate to cloak the loader malware in a way that it appears as legitimate to security products. That makes it especially dangerous as you won’t even realize you’ve been compromised.


Once it filters unnoticed through the security systems, it deploys a Remote Access Trojan (RAT) on the target system to get unauthorized access. To make matters worse, this malware can embed itself in legitimate libraries and can launch itself at system start-up before dropping its payload.

Tips to Protect Against Blister and Other Malware

If Blister malware sounds scary, you’ll want to know how to stop yourself falling victim. So what preventive measures can you take against emerging malware like Blister?

Here are some valuable tips to bear in mind:

  • Only use trusted and robust antivirus and malware/anti-spyware software. While it might not detect Blister itself, patches might be made available to correct this, and a strong security suite is worth its weight in gold when coming into contact with any threats.
  • Scan your Operating System (OS) for threats regularly and monitor the settings.
  • Always keep your OS up to date and set up automatic updates.
  • When connecting to the internet, only use secure and encrypted networks.
  • Employ browser common sense when surfing online, and do not click on pop-ups and ads.
  • Keep your personal information secure; do not share it with anyone.
  • Do not trust emails from unknown senders, especially if they contain website links or attachments. Don’t open the links or attachments inside such emails.
  • Only download files and programs from reliable and official sources.
  • Stay up-to-date with news on the latest malware attacks.

Malware is extremely prevalent and more than two million different malware threats are created each day. By taking preventive measures, we can minimize malware attacks and stay proactive with our security.

Avoid Getting Infected by Malware

Malware has many permutations—computer viruses, spyware, ransomware, and other unwanted software—that can be accidentally installed on our devices.

Once malware gets inside your device, it can leave an open door for cybercriminals to steal or encrypt your sensitive information, demand ransom money, send inappropriate ads, or simply make your device vulnerable to other types of attacks.

The best protection against malware is to avoid getting infected in the first place. You can win the battle against malware by taking simple measures like installing and updating your security software, using a robust firewall, setting your OS and browser to update automatically, and not downloading anything from unverified sources.

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