Yesterday, through a series of publications, we announced that we know about the biggest ransomware attack that began on Friday. Using one of NSA's exploits recently leaked by the Shadow Brokers team, attackers could infect computers world-wide with WannaCry (a Windows exploit embedded in NSA's EternalBlue tool).
Microsoft has already released Several updates about this vulnerability, but many users and organizations did not bother updating their systems.
The company in front of the devastating effects of the worm that continues to spread, overwhelmed and released updates for Windows XP, Windows (server) 2003 and Windows 8.
Yesterday we also mentioned that in the malware code there was also a disabling switch in the form of a kill switch domain.
What does this mean in simple words? When malware detects that there is a specific domain, it stops infections. This domain was created (registered) earlier today by a researcher, who observed the dot-com in the reverse-engineered binary. When the listing was detected by the malicious software, the ransomware distribution, and its worldwide spread, was immediately stopped.
But let's make it clear what the kill switch does:
The kill switch can not help devices that are already infected and locked with WannaCry.
By registering the domain and then moving it to a server environment that is meant to record and keep the sinkhole MalwareTech essentially bought time for systems that are not already infected.
"Fortunately, MalwareTech had the infrastructure to create a sinkhole," said Darien Huss, senior security research engineer at Proofpoint Security Company.
"If someone had bought the doamin and was not prepared then we would see too many infections right now."
If the installation did not have enough space and the server did not have enough bandwidth, the malware would not be trapped and would not be self-destructing.
Let's add that the discovery of MalwareTech is not a permanent solution. All it takes to get started again is a new WannaCry executive whose code will block the kill switch or use a more sophisticated URL generator instead of a static IP address.
However, the discovery of MalwareTech has helped slow down the process.
We hope that with so many security analysts who observe and analyze the behavior of WannaCry malware with reverse engineering, someone else will eventually find a more permanent disabling solution. Every minute counts ....