What is EternalBlue?

In our increasingly digital world, we are frequently confronted with new threats that affect us all, from individuals users to multinational organizations. The EternalBlue exploit is a prime example given that it has been at the center of many high-profile cyberattacks. In this blog post, we will go over what EternalBlue is, how it works, and what you can do to stay protected:

What is the EternalBlue exploit?

EternalBlue is an exploit specific to Microsoft, which the National Security Agency (NSA) used for gathering intelligence. Officially tagged as MS17-010 by Microsoft, this exploit gave the NSA a secret path into devices running Windows systems, such as Windows XP and Windows 7. For five years, the NSA knew about a vulnerability in Microsoft’s SMBv1 (Server Message Block version 1), a protocol used for sharing files. 

However, before they could inform Microsoft, a notorious group of hackers called the Shadow Brokers leaked this information. This leak put countless users in danger, and it highlighted the potential risks associated with the NSA’s practice of developing and preserving hidden access points, or ‘backdoors’, in software.

How was EternalBlue created?

The National Security Agency (NSA) created EternalBlue after years of probing Microsoft software for potential weak spots. Upon discovering a flaw in the SMBv1 protocol, the agency created this exploit as a tool to leverage that weak point.

Rather than notifying Microsoft of the imminent threat its users were exposed to, the NSA harnessed EternalBlue for five years, using it in counterterrorism and intelligence gathering operations. This incident illustrates the NSA’s habit of using exploits and hidden software entry points, known as ‘backdoors’.

Only when the NSA chose to inform Microsoft did the tech giant take action to mend the flaw. Microsoft swiftly rolled out patches to fix the exploit, but unfortunately for many users, this move was too late. 

How does the EternalBlue exploit work?

EternalBlue took advantage of a flaw in the less secure SMBv1 protocol, a communication tool that enabled Microsoft systems to interact with each other – for instance, performing tasks like file sharing and printing. However, this protocol was susceptible to exploitation.

To launch an EternalBlue attack, intruders merely needed to send a malicious data packet via SMBv1 to a vulnerable Windows server. This packet served as a trojan horse for malware, which could quickly spread to other devices running the susceptible software.

After the Shadow Brokers exposed the exploit in 2017, cybercriminals seized the opportunity, exploiting the vulnerability to launch devastating attacks and distribute malware on an unprecedented scale. Two major incidents stand out as clear demonstrations of the havoc wrought by this vulnerability:

1. The WannaCry ransomware attack on May 12, 2017 used the EternalBlue exploit to spread rapidly and infect 230,000 Windows PCs in 150 countries within just 24 hours. It held data hostage at a mind-boggling rate of 10,000 devices every hour, demanding payment from its victims.

2. The NotPetya ransomware attack, also in 2017, took advantage of EternalBlue to spread across Microsoft devices worldwide. The malware would embed itself, lock up the data residing on the targeted device, and then brazenly demand a ransom of $300 for a decryption key to unlock the hostage data.

Related Read: List of Ransomware Attacks

Is EternalBlue still a threat?

Despite its diminished impact, EternalBlue remains a potential threat in certain circumstances. While Microsoft has issued fixes to address the exact vulnerability exploited by EternalBlue, there are still instances in which systems may remain unpatched or outdated. In such cases, EternalBlue can still be dangerous, especially if used by sophisticated attackers.

Are you safe from the EternalBlue exploit?

Back in 2017, Microsoft patched the vulnerability that EternalBlue exploited after the NSA brought it to their attention. So, if your Windows devices are up to date, you have nothing to worry about.

However, did you know that EternalBlue attacks still take place? Every month, over 20 million attempts to exploit EternalBlue are prevented by Avast. So, should you be concerned? Not if you keep your software up to date. 

How to protect yourself against EternalBlue

Here are some effective ways to keep yourself say from online threats like EternalBlue:

Use anti-malware software

It is important to safeguard your device with robust anti-malware software. These solutions act as a shield against malicious software and various cyber threats. However, bear in mind that while these tools enhance your security, no solution can offer absolute protection in the dynamic landscape of cybersecurity.

Keep software updated 

Ensure that your Windows operating system is always up to date with the most recent Microsoft security patches and upgrades. Check for updates regularly and apply them as soon as possible.

Beware of suspicious links

Even though the threat of EternalBlue may be in the past, you could inadvertently download malware by clicking on a risky link. Phishing emails often lure you into visiting websites that harbor harmful software designed to compromise your device. For your safety, avoid clicking on links within online messages unless you are wholly confident of the sender’s authenticity.

Regularly backup your data

Regular data backups ensure that even if your system is compromised, your data is safe. Using a combination of cloud and offline backups provides robust protection. Backups should be done regularly, based on how often your data changes.

Frequently asked questions

Is Windows 7 still vulnerable to EternalBlue?

Yes, Windows 7 can be vulnerable to EternalBlue if it has not been updated with the necessary patches that Microsoft released to address this exploit. Microsoft discontinued support for Windows 7 in January 2020, making it even more important for users of this operating system to upgrade to a newer, supported version to ensure they receive crucial security updates.

Has EternalBlue been patched?

Yes, Microsoft released a security update in March 2017, officially known as MS17-010, to fix the vulnerability in the SMBv1 protocol that EternalBlue exploited. 

What was the vulnerability in EternalBlue?

The vulnerability in EternalBlue was related to the SMBv1 protocol, which Microsoft devices use for communication. A security weakness in this protocol allowed attackers to exploit it and gain unauthorized access to systems.

Does EternalBlue still work?

The EternalBlue exploit may still work against systems that have not had the underlying vulnerability patched or updated. It is strongly advised to keep your operating system up to date to protect against such vulnerabilities.

Final Word

EternalBlue is a well-known exploit that affects previous versions of Microsoft Windows. It received a lot of attention because of its role in the devastating WannaCry and NotPetya ransomware attacks in 2017. It is critical to keep your operating systems and applications up to date, use strong antivirus software, and practice safe browsing practices. By adopting these actions, you can strengthen your digital defenses against cyber threats.