But it’s not true, neither the threat is over yet.
However, the kill switch has just slowed down the infection rate.
Updated: Multiple security researchers have claimed that there are more samples of WannaCry out there, with different ‘kill-switch’ domains and without any kill-switch function, continuing to infect unpatched computers worldwide (find more details below).
For those unaware, WannaCry is an insanely fast-spreading ransomware malware that leverages a Windows SMB exploit to remotely target a computer running on unpatched or unsupported versions of Windows.
The SMB exploit, currently being used by WannaCry, has been identified as EternalBlue, a collection of hacking tools allegedly created by the NSA and then subsequently dumped by a hacking group calling itself “The Shadow Brokers” over a month ago.
“If NSA had privately disclosed the flaw used to attack hospitals when they *found* it, not when they lost it, this may not have happened,” NSA whistleblower Edward Snowden says.
The above-mentioned domain is responsible for keeping WannaCry propagating and spreading like a worm, as I previously explained that if the connection to this domain fails, the SMB worm proceeds to infect the system.
Fortunately, MalwareTech registered this domain in question and created a sinkhole – tactic researchers use to redirect traffic from the infected machines to a self-controlled system. (read his latest blog post for more details)Updated: Matthieu Suiche, a security researcher, has confirmed that he has found a new WannaCry variant with a different domain for kill-switch function, which he registered to redirect it to a sinkhole in an effort to slows down the infections.
The newly discovered WannaCry variant works exactly like the previous variant that wreaked havoc across the world Friday night.
But, if you are thinking that activating the kill switch has completely stopped the infection, then you are mistaken.
Since the kill-switch feature was in the SMB worm, not in the ransomware module itself., “WannaCrypt ransomware was spread normally long before this and will be long after, what we stopped was the SMB worm variant,” MalwareTech told The Hacker News.
You should know that the kill-switch would not prevent your unpatched PC from getting infected, in the following scenarios:
- If you receive WannaCry via an email, a malicious torrent, or other vectors (instead of SMB protocol).
- If by chance your ISP or antivirus or firewall blocks access to the sinkhole domain.
- If the targeted system requires a proxy to access the Internet, which is a common practice in the majority of corporate networks.
- If someone makes the sinkhole domain inaccessible for all, such as by using a large-scale DDoS attack.
MalwareTech also confirmed that some “Mirai botnet skids tried to DDoS the [sinkhole] server for lulz,” in order to make it unavailable for WannaCry SMB exploit, which triggers infection if the connection fails. But “it failed hardcore,” at least for now.Initially, this part of story was based on research of a security researcher, who earlier claimed to have the samples of new WannaCry ransomware that comes with no kill-switch function. But for some reason, he backed off. So, we have removed his references from this story for now.
However, shortly after that, we were confirmed by Costin Raiu, the director of global research and analysis team at Kaspersky Labs, that his team had seen more WannaCry samples on Friday that did not have the kill switch.
“I can confirm we’ve had versions without the kill switch domain connect since yesterday,”
Updated: WannaCry 2.0 is Someone Else’s Work
Raiu from Kaspersky shared some samples, his team discovered, with Suiche, who analysed them and just confirmed that there is a WannaCrypt variant without kill switch, and equipped with SMB exploit that would help it to spread rapidly without disruption.
What’s even worse is that the new WannaCry variant without a kill-switch believed to be created by someone else, and not the hackers behind the initial WannaCry ransomware.
“The patched version matt described does attempt to spread. It’s a full set which was modified by someone with a hex editor to disable the kill switch,” Raiu told me.
Updated: However, Suiche also confirmed that the modified variant with no kill switch is corrupted, but this doesn’t mean that other hackers and criminals would not come up with a working one.
“Given the high profile of the original attack, it’s going to be no surprise at all to see copycat attacks from others, and perhaps other attempts to infect even more computers from the original WannaCry gang. The message is simple: Patch your computers, harden your defences, run a decent anti-virus, and – for goodness sake – ensure that you have secure backups.” Cyber security expert Graham Cluley told The Hacker News.
Expect a new wave of ransomware attack, by initial attackers and new ones, which would be difficult to stop, until and unless all vulnerable systems get patched.
“The next attacks are inevitable, you can simply patch the existing samples with a hex editor and it’ll continue to spread,” Matthew Hickey, a security expert and co-founder of Hacker House told me.
“We will see a number of variants of this attack over the coming weeks and months so it’s important to patch hosts. The worm can be modified to spread other payloads not just WCry and we may see other malware campaigns piggybacking off this samples success.”
Even after WannaCry attacks made headlines all over the Internet and Media, there are still hundreds of thousands of unpatched systems out there that are open to the Internet and vulnerable to hacking.
“The worm functionality attempts to infect unpatched Windows machines in the local network. At the same time, it also executes massive scanning on Internet IP addresses to find and infect other vulnerable computers. This activity results in large SMB traffic from the infected host,” Microsoft says.
Believe me, the new strain of WannaCry 2.0 malware would not take enough time to take over another hundred of thousand vulnerable systems.