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'Accidental Hero' Finds Kill Switch To Stop Wana Decrypt0r Ransomware (theguardian.com)

"An 'accidental hero' has halted the global spread of the WannaCry ransomware that has wreaked havoc on organizations..." writes The Guardian. An anonymous reader quotes their report: A cybersecurity researcher tweeting as @malwaretechblog, with the help of Darien Huss from security firm Proofpoint, found and implemented a "kill switch" in the malicious software that was based on a cyber-weapon stolen from the NSA. The kill switch was hardcoded into the malware in case the creator wanted to stop it from spreading. This involved a very long nonsensical domain name that the malware makes a request to -- just as if it was looking up any website -- and if the request comes back and shows that the domain is live, the kill switch takes effect and the malware stops spreading. Of course, this relies on the creator of the malware registering the specific domain. In this case, the creator failed to do this. And @malwaretechblog did early Friday morning (Pacific Time), stopping the rapid proliferation of the ransomware.
You can read their first-person account of the discovery here, which insists that registering the domain "was not a whim. My job is to look for ways we can track and potentially stop botnets..." Friday they also tweeted a map from the New York Times showing that registering that domain provided more time for U.S. sites to patch their systems. And Friday night they added "IP addresses from our [DNS] sinkhole have been sent to FBI and ShadowServer so affected organizations should get a notification soon. Patch ASAP."

UPDATE: Slashdot reader Lauren Weinstein says some antivirus services (and firewalls incorporating their rules) are mistakenly blocking that site as a 'bad domain', which allows the malware to continue spreading. "Your systems MUST be able to access the domain above if this malware blocking trigger is to be effective, according to the current reports that I'm receiving!"

12 of 182 comments (clear)

  1. Factsheet by Anonymous Coward · · Score: 5, Informative

    Here is a factsheet: https://gist.github.com/slider23/bd617d0d376047c05d18980fde306840
    The domain in question is "www.iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com".

    1. Re:Factsheet by Anonymous Coward · · Score: 5, Insightful

      Sadly not - with that long of a (presumably) randomly generated string, the odds that it is taken are so minuscule that you wouldn't bother checking, precisely because that might leave a trail. If I were doing the same thing, I'd generate a nice long random string and happily presume that it's still available.

  2. Here's how it works by Okian+Warrior · · Score: 4, Informative

    There's a good sumamry over at github.

    Essentially, the malware looks for port 445 (SMB) on local computers and the internet. If you have this port open on the internet, and have older than Win10, and haven't updated with the Mar 2 patch, then you're vulnerable.

    Note that WinXP has about 8% market share and cannot be patched. You can get infected from another machine on the local subnet as well.

    Here is a good detailed description of how it works and what it does.

    Note that the propagation has halted for now, however the virus also installs a rootkit on the user's machine. If the virus writer realizes that the domain has been taken, he could remotely change the hard-coded domain name on every currently-infected machine, thus restarting the propagation process.

    1. Re:Here's how it works by Anonymous Coward · · Score: 4, Informative
  3. Just wait for tomorrow's news... by Gravis+Zero · · Score: 4, Insightful

    A new version of WannaCry ransomware is on the loose!

    This is a game of cat and mouse, so don't assume you have won.

    --
    Anons need not reply. Questions end with a question mark.
    1. Re:Just wait for tomorrow's news... by StormReaver · · Score: 4, Insightful

      This is a game of cat and mouse, so don't assume you have won.

      The only way to win is to not play: get rid of Windows.

  4. NSA LIABILITY = $1 BILLION ? by Anonymous Coward · · Score: 5, Insightful

    Can the EU and UK sue the US NSA for damages caused by the exploitation of their dangerous creation?

    The "S" in NSA stands for "Security" -- but what happened here is the exact opposite of security, undoubtedly costing many actual lives (as people cannot go to particular hospitals, or have surgeries disrupted) and a huge amount of money, which could have been avoided if the NSA had instead helped SECURE the affected operating systems rather than developing a dangerous and effective software weapon which could be easily leaked and used by anyone on the planet to wreak havoc.

  5. Re:Why in hell... by OolimPhon · · Score: 5, Informative

    It doesn't have to expose SMB to the outside world.

    The exploit arrives as a phishing email. Once clicked, it looks for SMB on that machine. By using SMB, it can then infect other machines on the same network - and, more importantly, behind the firewall you carefully set up to block SMB from the Internet.

    Moral: don't click on things you get randomly from the Internet. Also, don't click on things you get unexpectedly from colleagues in the same organization.

  6. Re: But by Anonymous Coward · · Score: 5, Funny

    Damn script kiddies, get off my LAN!

  7. "Accidental" Hero? by gurps_npc · · Score: 5, Insightful

    That sounds pejorative to me. Most discoveries involve accidents - just ask Alexander Fleming, Christopher Colombus, or Doctor Spencer Silver (post it notes).

    Like all of these men, this HERO, was investigating something not fully understood, stumbled by accident on something interesting, REALIZED that it was interesting and worked hard to understand exactly what it was. The realization and hard work are not common, they make the difference between a real discovery and a random day.

    This is no more accidental than 90% of scientific discoveries.

    --
    excitingthingstodo.blogspot.com
  8. Re:Windows by Highdude702 · · Score: 4, Informative

    uhh you realize last month this effected 90% of windows systems? new and old? microsoft decided that older versions of windows didnt matter anymore. even know in the 90's they convinced all kinds of Cat Scan and MRI makers to install windows XP or even worse windows SE on their machines for ease of use.. and now they refuse to give updates to people that paid $200,000-$5,000,000 for their computers. sounds like shitty business practice to me. Now i understand microsoft didnt sell the people the machines. but they did a damn good job of making sure their shitty OS was inside of them.

  9. Re: Windows by Aristos+Mazer · · Score: 4, Insightful

    It should be straightforward to hide those unpatched machines behind a proxy. Give them an Ethernet connection to only one other machine and let that other machine be fully patched and updatable. That's a fix, but, honestly, I'm confused why critical medical equipment is fully exposed to the network in the first place.