We have yet another change today to the downloaders from the Necurs botnet that deliver Locky ransomware or Trickbot banking trojan. It has been a bit quiet over the last few days, so we have been expecting trouble.
I posted recently about Necurs delivering a different payload, either Locky or Trickbot based on your IP address, when contacting the download sites. I saw a few twitter links leading to this post on Bleeping Computer saying that Locky ( Necurs Downloaders) will take screenshots of the “victim’s” computer and send back error messages to base.
Well today they have updated that and changed to be even more selective. You don’t even get a download link or location unless your IP address is in the range they have decided that will be today’s target. They are using a post form info to a website http://haddownding.net/trtrtr.php that only responds from certain IP addresses and that will only give a list of download locations if it thinks you are a genuine computer not a researcher or antivirus company or sandbox. They send all sorts of information from your computer, to decide if they will give the malware to you and what malware to deliver.
The delivery method of the actual is getting very complicated and harder to block. Luckily for prospective victims, the delivery emails are so stupid that nobody should fall for them. Todays is an email pretending to come from invoicing@random names and email addresses, with a subject like Invoice 009863361 10.18.2017 where the numbers are random with a blank / empty body
They use email addresses and subjects that will entice, persuade, scare or shock a recipient to read the email and open the attachment.
Thanks to various Twitter contacts ( my grateful thanks to them all for their hard work and expert knowledge) we have some downloads sites delivering Locky ransomware using USA IP numbers ( VirusTotal) ( Payload Security ) from these locations:
One of the emails looks like:
From: Invoicing <Invoicing@ random name>
Date: Wed 18/10/2017 10:27
Subject: Invoice 009863361 10.18.2017
Attachment: Invoice 009863361 10.18.2017.7z
totally empty blank
All the alleged senders, amounts, reference numbers, Bank codes, companies, names of employees, employee positions, email addresses and phone numbers mentioned in the emails are all random. Some of these companies will exist and some won’t. Don’t try to respond by phone or email, all you will do is end up with an innocent person or company who have had their details spoofed and picked at random from a long list that the bad guys have previously found. The bad guys choose companies, Government departments and organisations with subjects that are designed to entice you or alarm you into blindly opening the attachment or clicking the link in the email to see what is happening.
Please read our How to protect yourselves page for simple, sensible advice on how to avoid being infected by this sort of socially engineered malware.
Previous campaigns over the last few weeks have delivered numerous different download sites and malware versions. There are frequently 5 or 6 and even up to 150 download locations on some days, sometimes delivering the exactly same malware from all locations and sometimes slightly different malware versions. Locky does update at frequent intervals during the day, sometimes as quickly as every hour, so you might get a different version of these nasty Ransomware.
This is another one of the files that unless you have “show known file extensions enabled“, can easily be mistaken for a genuine DOC / PDF / JPG or other common file instead of the .EXE / .JS file it really is, so making it much more likely for you to accidentally open it and be infected.
Be very careful with email attachments. All of these emails use Social engineering tricks to persuade you to open the attachments that come with the email. Whether it is a message saying “look at this picture of me I took last night” and it appears to come from a friend or is more targeted at somebody who regularly is likely to receive PDF attachments or Word .doc attachments or any other common file that you use every day.
The basic rule is NEVER open any attachment to an email, unless you are expecting it. Now that is very easy to say but quite hard to put into practice, because we all get emails with files attached to them. Our friends and family love to send us pictures of them doing silly things, or even cute pictures of the children or pets.
Never just blindly click on the file in your email program. Always save the file to your downloads folder, so you can check it first. Many malicious files that are attached to emails will have a faked extension. That is the 3 letters at the end of the file name. Unfortunately windows by default hides the file extensions so you need to Set your folder options to “show known file types. Then when you unzip the zip file that is supposed to contain the pictures of “Sally’s dog catching a ball” or a report in word document format that work has supposedly sent you to finish working on at the weekend, or an invoice or order confirmation from some company, you can easily see if it is a picture or document & not a malicious program.
If you see .JS or .EXE or .COM or .PIF or .SCR or .HTA .vbs, .wsf , .jse .jar at the end of the file name DO NOT click on it or try to open it, it will infect you.
While the malicious program is inside the zip file, it cannot harm you or automatically run. When it is just sitting unzipped in your downloads folder it won’t infect you, provided you don’t click it to run it. Just delete the zip and any extracted file and everything will be OK. You can always run a scan with your antivirus to be sure. There are some zip files that can be configured by the bad guys to automatically run the malware file when you double click the zip to extract the file. If you right click any suspicious zip file received, and select extract here or extract to folder ( after saving the zip to a folder on the computer) that risk is virtually eliminated. Never attempt to open a zip directly from your email, that is a guaranteed way to get infected. The best way is to just delete the unexpected zip and not risk any infection.