When I saw this email, I was convinced it was going to be another phishing email, but no it quite cleverly downloads malware via a complicated chain. I don’t know what malware this eventually delivers.
It all starts with the pdf which looks like
The link goes to https://bitly.com/secured-pdf-online which redirects to http://exch-unitedremitx.pw/ima/Add-On/HOTTUSD198000_pdf.html where you see a webpage looking like this telling you that you need to install plugin to view the content
The PDF ( VirusTotal) ( Payload Security) This is where it gets a bit weird & unusual. as you can see from the screenshots above the link goes to https://bitly.com/secured-pdf-online but examining the PDF shows a different embedded url http://bit.ly/2wTMuYg which is marked as a phishing/malware redirector and has been live since September 2016. The site it redirects is now giving a 404 http://cloudy-exch.pw/invoice/update.HTML. We posted about that phishing campaign back in September 2017 https://myonlinesecurity.co.uk/email-credential-phishing-via-fake-emirates-bank-statement-and-fake-generic-proforma-invoice-scams/
It looks like the criminals have reused an old PDF and not cleaned it up properly since last use. I can’t understand why examining the PDF won’t show the proper link, or how they have hidden it.
From: scans <firstname.lastname@example.org>
Date: Thu 26/10/2017 18:47
Subject: Invoice copy
Attachment: new_invoice payment.pdf
|18.104.22.168||mail.cfsww.org||US||AS7922 Comcast Cable Communications, LLC|
Received: from mail.cfsww.org ([22.214.171.124]:3699)
by knight.knighthosting.co.uk with esmtps (TLSv1:ECDHE-RSA-AES256-SHA:256)
for email@example.com; Thu, 26 Oct 2017 18:47:25 +0100
Received: from SERVER2013.cfsww.local ([fe80::5169:f754:52b0:b30f]) by
SERVER2013.cfsww.local ([fe80::5169:f754:52b0:b30f%10]) with mapi id
14.01.0438.000; Thu, 26 Oct 2017 10:47:22 -0700
From: scans <firstname.lastname@example.org>
To: “email@example.com” <firstname.lastname@example.org>
Subject: Invoice copy
Thread-Topic: Invoice copy
Date: Thu, 26 Oct 2017 17:47:22 +0000
x-originating-ip: [126.96.36.199] Content-Type: multipart/mixed;
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.