Last Updated on July 9, 2024 by Arnav Sharma

EternalBlue may sound like a tropical getaway, but it’s far from it. This notorious exploit poses a significant threat to computer systems and data worldwide. Developed by the US National Security Agency (NSA) and later leaked by the hacker group Shadow Brokers, EternalBlue has facilitated some of the most devastating cyberattacks in history. In this blog, we’ll explore what EternalBlue is, how it works, its impact, and how you can protect your systems from this enduring threat.

What is EternalBlue Exploit?

EternalBlue is an exploit targeting a series of vulnerabilities in the Microsoft SMBv1 (Server Message Block version 1) protocol. These vulnerabilities, cataloged from CVE-2017-0143 to CVE-2017-0148, allow remote attackers to execute arbitrary code on a target system by sending specially crafted packets. The exploit, officially named MS17-010 by Microsoft, was developed by the NSA as part of their cyber arsenal for intelligence gathering.

How Does EternalBlue Work?

EternalBlue exploits flaws in the SMBv1 protocol, which facilitates file and print services on Windows networks. The exploit involves several bugs:

  1. Buffer Overflow: A mathematical error in handling the File Extended Attribute (FEA) list structure causes a buffer overflow, allowing data to overflow into adjacent memory space.
  2. Validation Error: The SMB protocol’s definition difference between SMB_COM_TRANSACTION2 and SMB_COM_NT_TRANSACT sub-commands creates a mismatch in memory allocation.
  3. Heap Spraying: Attackers can use this technique to allocate memory at a specific address and execute shellcode to take control of the system.

EternalBlue Developed by the NSA

EternalBlue was developed by the NSA as part of their controversial program of stockpiling and weaponizing cybersecurity vulnerabilities. The NSA used EternalBlue for years to gather intelligence before it was leaked by the Shadow Brokers in April 2017. The leak exposed the vulnerability to the world, leading to widespread cyberattacks.

How EternalBlue Was Leaked

The Shadow Brokers, a notorious hacking group, leaked EternalBlue in April 2017. The group published the exploit online, making it accessible to cybercriminals worldwide. This leak allowed hackers to exploit the vulnerability in Microsoft Windows systems, leading to massive cyberattacks like WannaCry and NotPetya.

How EternalBlue Was Used in Cyberattacks

EternalBlue has been the foundation for numerous high-profile cyberattacks:

  • WannaCry: This ransomware attack, launched on May 12, 2017, leveraged EternalBlue to spread rapidly across networks, encrypting data on over 230,000 systems in 150 countries. Major organizations like FedEx and the UK National Health Service (NHS) were significantly impacted, resulting in billions of dollars in damages.
  • Petya/NotPetya: Initially launched in 2016, Petya became infamous in 2017 when its variant, NotPetya, used EternalBlue to cause widespread destruction. Unlike typical ransomware, NotPetya permanently encrypted system files, making data recovery impossible even if the ransom was paid.
  • Indexsinas: This computer worm, active since 2019, uses EternalBlue to infect and replicate across networks, often used for malicious activities like cryptocurrency mining.

Why EternalBlue is Still a Threat

Despite the release of the MS17-010 security patch by Microsoft on March 14, 2017, many systems remain unpatched. Researchers estimate that around 20 million Windows machines are still vulnerable to EternalBlue. The continued use of SMBv1 in some systems exacerbates the risk. EternalBlue’s ability to spread malware and facilitate cyberattacks keeps it relevant and dangerous.

Exploiting EternalBlue: How to Protect Against It

  1. Apply Patches: Ensure all systems are updated with the MS17-010 patch to close the EternalBlue vulnerability.
  2. Disable SMBv1: If possible, disable the SMBv1 protocol on all devices to prevent exploitation.
  3. Use Antivirus Software: Install reputable antivirus software, such as AVG AntiVirus, to detect and block threats on Windows operating systems.
  4. Implement EDR Solutions: For businesses, deploy Endpoint Detection and Response (EDR) solutions to monitor and mitigate potential exploits.

EternalBlue serves as a stark reminder of the dangers posed by unpatched vulnerabilities and the importance of robust cybersecurity measures. By understanding what EternalBlue is and taking proactive steps to protect your systems, you can mitigate the risks associated with this exploit and safeguard your digital assets. Regular updates and vigilant security practices are essential in the ongoing battle against cyber threats.


Q: What versions of Windows are affected by the EternalBlue exploit?

A: Operating Systems: Windows 7, Windows Server 2008 and R2, Windows 10, Windows Server 2012, Windows XP, Windows Vista, Windows Server 2016, Windows 8.1, Windows Server 2003, Windows 8, Windows RT 8.1

Q: What is EternalBlue still considered?

A: EternalBlue is still considered a significant threat to Windows users due to its remote code execution vulnerability on Windows operating systems.

Q: Which framework can be used for penetration testing with the EternalBlue exploit?

A: Metasploit framework

Q: What is EternalRocks and how is it related to EternalBlue?

A: EternalRocks is a malware that uses seven exploits, including the EternalBlue exploit, to spread.

Q: How can you determine if a target is vulnerable to EternalBlue?

A: By checking if the target is running older Windows versions or versions of Windows that have not been patched against MS17-010.

Q: What action did Microsoft take in response to the EternalBlue threat?

A: Microsoft released security updates to patch the vulnerability exploited by EternalBlue.

Q: What is the significance of MS17-010 in relation to EternalBlue?

A: MS17-010 is the security update released by Microsoft to address the SMB remote Windows kernel pool corruption vulnerability exploited by EternalBlue.

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