Important – New Fax Received Malspam Delivers Trickbot Banking Trojan

Trojan

A slightly unusual email with the subject of Important – New fax received pretending to come from Administrator <Administrator@internalfax.net> or Administrator <Administrator@internalfax.com> with either a malicious word doc attachment or a zip file containing a .js file which downloads Trickbot banking Trojan. It is very unusual to see the same banking Trojan, (although different versions ) being malspammed out concurrently, using the same email template but different file attachments and coming from 2 almost identical domains a .net and a.com

They are using email addresses and subjects that will scare or 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.

internalfax.net or internalfax.com are sending these emails out. They are newly registered and look like they were created for the purpose of spreading malware

The email looks like:

From: Administrator <Administrator@internalfax.net> or Administrator <Administrator@internalfax.com>

Date: Fri 28/10/2021 17:15

Subject: Important – New fax received

Attachment: InternalFax.doc or InternalFax.zip ( containing InternalFax.js)

Body Content:

Date: 10/28/2021
Recipient: aberkinnuji@thespykiller.co.uk
From: 501-244-2883
Attn:

Important document: For internal use only

The documents are ready. Check attached file for more information.

[THIS IS AN AUTOMATED MESSAGE – PLEASE DO NOT REPLY DIRECTLY TO THIS EMAIL]Confidentiality Notice: The information contained in this message may be confidential and legally privileged. It is intended only for use of the individual named. If you are not the intended recipient, you are hereby notified that the disclosure, copying, distribution, or taking of any action in regards to the contents of this fax – except its direct delivery to the intended recipient – is strictly prohibited. If you have received this fax in error, please notify the sender immediately and destroy this cover sheet along with its contents, and delete from your system, if applicable.

Screenshot:

Email Headers:

.net version

Received: from [104.130.31.240] (port=44820 helo=internalfax.net)
by knight.knighthosting.co.uk with esmtp (Exim 4.87)
(envelope-from <Administrator-a72917d5=thespykiller.co.uk@internalfax.net>)
id 1c09op-00082Q-Dh
for a72917d5@thespykiller.co.uk; Fri, 28 Oct 2021 17:15:47 +0100
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; s=key; d=internalfax.net;
h=Mime-Version:Date:To:Subject:From:Content-Type:Message-ID;
bh=hnayc/LaLMjEHH9CrADeY5UWzAk=;
b=mjEMvR1GkMsaOq4lnp62i0a+dYEB2ulFBsoAmjCEQ/HHesqONCvmP3OHK7zF66VapElYdks/QFJ4
L5NG+47qtcbB4movLSk++U1I2U5lr0abmknJdaldaNXBcnZ0jbhnpvk4WYZgIxxOoCABmrCFdN2N
7jc1YUrv3T4NNzy/PH5BZJ/5qjbYogLhUTmN914Nym4GuI/SKJV9VHrdmVGaJIs7Q2JeCPQjppZn
hGkiUk0JbOHzFNmQzjnIjOpzVYyTd89+t9yQxvrnD81Ew6PIexs9JP4LF/hfxhi0UIfuS4EDGiyQ
xgGmH16stIOjq0eQukrsnrq5FQxLAJ1FA5LUoQ==
Received: by internalfax.net id h2dsr84rl68l for <a72917d5@thespykiller.co.uk>; Fri, 28 Oct 2021 12:15:05 -0400 (envelope-from <Administrator-a72917d5=thespykiller.co.uk@internalfax.net>)
Mime-Version: 1.0
Date: Fri, 28 Oct 2021 12:15:05 -0400
To: a72917d5@thespykiller.co.uk
Subject: Important – New fax received
From: “Administrator” Administrator@internalfax.net
Content-Type: multipart/mixed;
boundary=87588d663fb6cf9398b7d36a9ef20e29
Message-ID: <0.0.0.0.1D23136720AEC6A.8BC64A6@internalfax.net>

.com version

Received: from internalfax.com ([104.130.31.227]:50249)
by knight.knighthosting.co.uk with esmtp (Exim 4.87)
(envelope-from <Administrator-aberkinnuji=thespykiller.co.uk@internalfax.com>)
id 1c09qR-0008B9-SM
for aberkinnuji@thespykiller.co.uk; Fri, 28 Oct 2021 17:17:30 +0100
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; s=key; d=internalfax.com;
h=Mime-Version:Date:To:Subject:From:Content-Type:Message-ID;
bh=o6ZQB6OLCimOyaeM6qdRrkriCd4=;
b=UGp5Qn0aU9wUbUArD8UyQ+qeeEn2+HX/+EUyC2dQ6PU0HiaO7G2xk9nKsc3J+o8Q40B2vMNjzNOQ
gs2P/JWLP7UvJD4i2OhyTqlVjDdv9a3WKN+Jec+fpNAbXwou78QQbO3EVdkgkZzquC/EK9AOG7Y3
R6CyAJih3o3s3iwJouACBt0bDf86tp2ekFMuIzQp3uz2iZNoLCLfsadMt9xtQu86sIHQQax80CXp
kX4pp4J0EwzuLNOaOKkLyJOpkkVUYWwIRg3h4dOllfHsN+/UPYA1y4ZQF1KywmZBk+yUynAqJwC5
oUGzT5N+AeEUVcKPhyZAhPZct8xW5gwBwVkKYw==
Received: by internalfax.com id h2dt1g4qq2g4 for <aberkinnuji@thespykiller.co.uk>; Fri, 28 Oct 2021 12:15:13 -0400 (envelope-from <Administrator-aberkinnuji=thespykiller.co.uk@internalfax.com>)
Mime-Version: 1.0
Date: Fri, 28 Oct 2021 12:15:13 -0400
To: aberkinnuji@thespykiller.co.uk
Subject: Important – New fax received
From: “Administrator” Administrator@internalfax.com
Content-Type: multipart/mixed;
boundary=756e2f7578a3f004c144245bd781ff03
Message-ID: <0.0.0.0.1D2313676701C8A.7B1FB94@internalfax.com>

Both emails pass all validation checks, SPF & DKIM so blow past spam filters and both domains are newly registered today, with the sole aim of spreading malware. Domains are both registered by and hosted by Godaddy

28 October 2021 : InternalFax.js Current Virus total detections: MALWR shows a download from http://www.tessaban.com/admin/images/jsjsjsihfsdkq.png which of course is not a png but a renamed .exe file. The JavaScript renames it to vQjiLVqR.exe and autoruns it. ( VirusTotal ) Payload Security was unable to contact any download sites or download the malware

28 October 2021: InternalFax.doc VirusTotal | Payload Security shows a download from futuras.comdodocdoddus.exe which is renamed to 10575.exe and autorun by the macro in the word doc ( VirusTotal) MALWR shows the downloads from either http://futuras.com/dodocdoddus.exe or http://fax-download.com/lindoc1.exe ( fax-download.com registered yesterday 27 October 2021 and hosted on 23.95.37.89 host.colocrossing.com)

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. Dridex /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 or Banking password stealer Trojans.

All the alleged senders, companies, names of employees, phone numbers, amounts, reference numbers etc. mentioned in the emails are all innocent and are just picked at 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 other 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.

This email attachment contains what appears to be a genuine word doc or Excel XLS spreadsheet with either a macro script or an embedded OLE object that when run will infect you.

Modern versions of Microsoft office, that is Office 2010, 2013, 2016 and Office 365 should be automatically set to higher security to protect you.

By default protected view (https://support.office.com/en-gb/article/What-is-Protected-View-d6f09ac7-e6b9-4495-8e43-2bbcdbcb6653) is enabled and macros are disabled, UNLESS you or your company have enabled them. If protected view (https://support.office.com/en-gb/article/What-is-Protected-View-d6f09ac7-e6b9-4495-8e43-2bbcdbcb6653) mode is turned off and macros are enabled then opening this malicious word document will infect you, and simply previewing it in windows explorer or your email client might well be enough to infect you. Definitely DO NOT follow the advice they give to enable macros or enable editing to see the content.

Most of these malicious word documents either appear to be totally blank or look something like these images when opened in protected view (https://support.office.com/en-gb/article/What-is-Protected-View-d6f09ac7-e6b9-4495-8e43-2bbcdbcb6653) mode, which should be the default in Office 2010, 2013, 2016 and 365. Some versions pretend to have a digital RSA key and say you need to enable editing and Macros to see the content. Do NOT enable Macros or editing under any circumstances.

What Can Be Infected By This

At this time, these malicious macros only infect windows computers. They do not affect a Mac, IPhone, IPad, Blackberry, Windows phone or Android phone.

The malicious word or excel file can open on any device with an office program installed, and potentially the macro will run on Windows or Mac or any other device with Microsoft Office installed. BUT the downloaded malware that the macro tries to download is windows specific, so will not harm, install or infect any other computer except a windows computer. You will not be infected if you do not have macros enabled in Excel or Word. These Macros do not run in “Office Online” (https://products.office.com/en-gb/office-online/documents-spreadsheets-presentations-office-online) Open Office, Libre Office, Word Perfect or any other office program that can read Word or Excel files.

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. Also please read our post about word macro malware and how to avoid being infected by them

Be very careful with email attachments. All of these emails use Social engineering (https://en.wikipedia.org/wiki/Social_engineering_(security)) tricks to persuade you to open the attachments that come with the email. It might be a simple message saying “look at this picture of me I took last night” that appears to come from a friend. It might be a scare ware message that will make you open the attachment to see what you are accused of doing. Frequently it is more targeted at somebody ( small companies etc.) who regularly receive PDF attachments or Word .doc attachments or any other common file that you use every day, for example an invoice addressed to sales@victimcompany.com.

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. Many of us routinely get Word, Excel or PowerPoint attachments in the course of work or from companies that we already have a relationship with.

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. A lot of 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”, an invoice or receipt from some company for a product or service or receive a Word doc or Excel file report that work has supposedly sent you to finish working on at the weekend, 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.

With these malformed infected word, excel and other office documents that normally contain a vba macro virus, the vital thing is do not open any office document direct from your email client or the web. Always save the document to a safe location on your computer, normally your downloads folder or your documents folder and scan it with your antivirus. Many Antiviruses do not natively detect vba macro-viruses in real time protection and you need to enable document or office protection in the settings. Do not rely on your Anti-Virus to immediately detect the malware or malicious content. DO NOT enable editing mode or enable macros

All modern versions of word and other office programs, that is 2010, 2013, 2016 and 365, should open all Microsoft office documents that is word docs, excel files and PowerPoint etc that are downloaded from the web or received in an email automatically in “protected view” (https://support.office.com/en-gb/article/What-is-Protected-View-d6f09ac7-e6b9-4495-8e43-2bbcdbcb6653) that stops any embedded malware or macros from being displayed and running.

Make sure protected view is set in all office programs to protect you and your company from these sorts of attacks and do not over ride it to edit the document until you are 100% sure that it is a safe document. If the protected mode bar appears when opening the document DO NOT enable editing mode or enable macros the document will look blank or have a warning message, but will be safe.

Be aware that there are a lot of dodgy word docs spreading that WILL infect you with no action from you if you are still using an out dated or vulnerable version of word. This is a good reason to update your office programs to a recent version and stop using office 2003 and 2007. Many of us have continued to use older versions of word and other office programs, because they are convenient, have the functions and settings we are used to and have never seen a need to update to the latest super-duper version. The risks in using older version are now seriously starting to outweigh the convenience, benefits and cost of keeping an old version going.

I strongly urge you to update your office software to the latest version and stop putting yourself at risk, using old out of date software.

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