The EternalRocks worm is a new threat that comes hot on the heels of WannaCry ransomware. The self-replicating network work uses similar tactics to infect computers and spread to other connected devices; however, in contrast to the worm used to spread WannaCry ransomware, there is no kill switch. In fact, at present, there is also no malicious payload. That is unlikely to be the case for very long.

The WannaCry ransomware attacks were halted when a security researcher discovered a kill switch. Part of the infection process involved checking a nonsense domain that had not been registered. If no connection was made, the ransomware element would proceed and start encrypting files. By registering the domain, the encryption process didn’t start. Had the domain not been registered, the attacks would have been more far reaching, affecting more than the 300,000 computers believed to have been affected by the Friday 12 attacks.

New threats were predicted to be released in the wake of WannaCry, either by the same group or copycats. The EternalRocks worm therefore does not come as a surprise. That said, EternalRocks could be far more dangerous and cause considerably more harm than WannaCry.

The WannaCry ransomware attacks involved just used two exploits developed by the NSA – EternalBlue and DoublePulsar. EternalRocks uses six NSA hacking tools (EternalBlue, DoublePulsar, EternalChampion, EternalRomance, EternalSynergy, ArchiTouch and SMBTouch).

In addition to the Windows Server Message Block (SMBv1) and SMBv2 hacking tools, this threat uses a SMBv3 exploit in addition to a backdoor Trojan, the latter being used to spread infection to other vulnerable computers on a network. Two SMB reconnaissance tools have also been incorporated to scan open ports on the public Internet.

EternalRocks is also capable of hiding on the infected machine after deployment. With the WannaCry attacks, users were alerted that their computers had been compromised when the ransomware encrypted their files and a note was placed on the desktop.

Once on a computer, the EternalRocks worm waits for 24 hours before downloading the Tor browser, contacting the attackers, and replicating and spreading to other devices on the network.

The self-replicating network worm was discovered by security researcher Miroslav Stampar from CERT in Croatia. While the threat has only just been discovered, Stampar says the first evidence of infections dates back to May 3.

At present, the EternalRocks worm does not have any malicious payload. It neither installs malware nor ransomware, but that does not mean it poses no risk. Worms can be weaponized at any point, as was seen on Friday 12 May, when WannaCry ransomware was deployed.

For the time being, it is unclear how many computers have already been infected and how EternalRocks will be weaponized.

Preventing infection with EternalRocks worm and other similar yet to be released – or discovered – threats is possible by ensuring operating systems and software are patched promptly. Older operating systems should also be upgraded as soon as possible. As Kaspersky Lab reported, 95% of the WannaCry attacks affected Windows 7 devices. No Windows 10 devices were reportedly attacked.