Just a quick update to Emotet delivery campaigns that have plagued us for ages. I don’t normally post much about Emotet. There are lots of other researchers keeping an eye on it, who post regular updates via Twitter etc, Until recently Emotet was normally delivered via a malicious word doc attachment. Then about 10 days ago we noticed some versions using js attachments inside zip files. Yesterday evening we noticed yet another change. This time using js files inside password protected zips with a previously unknown password that might be different in each version received.
Using password protected zip files does help to bypass antivirus protections & perimeter defences.
The other difference with this particular sample is the fake error message that is popped up when running the js file. Which says Not Supported File Format. There was an error opening this document. The file is damaged and could not be repaired (for example, it was sent as an email attachmentand wasn’t correctly decoded). When you press OK, the malware continues to run. At this time I am not certain what the final payload is. Emotet is currently being used as a downloader for multiple other malware families. It does use geo-IP targeting, so running this sample in an online sandbox didn’t give much of a result.
This malware js file contacts one of these 3 urls to download the next stage
I got my initial payload from the second url. which gave me This file VirusTotal | Anyrun App | Trying to run this via Anyrun using tor & a US proxy hasn’t given any additional payloads for me. So it is almost certain that the information being sent back to the C2 is not being accepted as a proper computer on an IP in the targeted range, so no additional payloads are being offered or downloaded.
They use email addresses and subjects that will entice a user to read the email and open the attachment. A very high proportion are being targeted at small and medium size businesses, with the hope of getting a better response than they do from consumers. As usual this particular email is nothing special & just generic enough to be confused with a genuine email, although pretending to come from your company as the sender name. These emails do generally come via the domain in the from box, which are normally compromised email accounts from previous phishing or malware campaigns.
Remember many email clients or webmail services, especially on a mobile phone or tablet, only show the Name in the From: and not the bit in <domain.com >. That is why these scams and phishes and malware deliveries work so well.
You can now submit suspicious sites, emails and files via our Submissions system
One of the emails looks like:
From: Victim.co <firstname.lastname@example.org>
Date: Wed 03/04/2019 15:01 ( US time) arrived at 22:10 UTC+1
Subject: March Statement – Victim.co
Please see/review attached.
The password for the document is U720StaMarch
These malicious attachments normally have a password stealing component, with the aim of stealing your bank, PayPal or other financial details along with your email or FTP ( web space) log in credentials. Many of them are also designed to specifically steal your Facebook and other social network log in details. A very high proportion are Ransomware versions that encrypt your files and demand money ( about £350/$400) to recover the files.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.
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.
|220.127.116.11||66.subnet18.104.22.168.in-addr.arpa||US||AS6939 Hurricane Electric LLC|
|22.214.171.124||fixed-187-189-190-146.totalplay.net||Guadalajara||Jalisco||MX||AS17072 TOTAL PLAY TELECOMUNICACIONES SA DE CV|
Received: from server.jscholarpublishers.com ([126.96.36.199]:51418) by my email server with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91) (envelope-from <email@example.com>) id 1hBn8o-00067I-K2 for firstname.lastname@example.org; Wed, 03 Apr 2019 22:09:51 +0100 Received: from [188.8.131.52] (fixed-187-189-190-146.totalplay.net [184.108.40.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by server.jscholarpublishers.com (Postfix) with ESMTPSA id 0C0277AB91 for <email@example.com>; Wed, 3 Apr 2019 10:01:30 -0400 (EDT) Date: Wed, 03 Apr 2019 08:01:29 -0600 From: victim.co <firstname.lastname@example.org> To: email@example.com Subject: March Statement - victimsdomain.co MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_14812_1309532037.23439794302303643238"
Main object- “March___Statement___2019_04___BIZ_6896390624277668806___265639967.js”
Dropped executable file
sha256 C:\Users\admin\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\K78MRVB5\4_uJ.exe aa4ae06286b7932529389721446012ec1a68a3ed83c13ebe197d91e60b1a59f4
sha256 C:\Users\admin\AppData\Local\eventswrap\K03PJh.exe a186a24cdd085c6b4f3bb2136f1c11a3ca7475fa08e91703723797ba8cf7778b
Main object- “W_dK”
Dropped executable file
sha256 C:\Users\admin\AppData\Local\eventswrap\eventswrap.exe aa4ae06286b7932529389721446012ec1a68a3ed83c13ebe197d91e60b1a59f4
sha256 C:\Users\admin\AppData\Local\eventswrap\PUJ5SQ.exe a186a24cdd085c6b4f3bb2136f1c11a3ca7475fa08e91703723797ba8cf7778b