Trickbot Via Fake Efax Message Using Squiblydoo, Active X, Macro And Abusing Pastebin

Fake Document

We are seeing massive changes with the Trickbot delivery campaign overnight. I have only seen 1 mention on Twitter (https://twitter.com/executemalware/status/1108120575044653057) about this campaign and 1 on a private malware research mailing list, so it can’t be affecting too many recipients.

This example is today’s latest spoof or imitation of a well-known company, bank or public authority delivering Trickbot banking Trojan. The email with the subject of “You have a new eFax message! ” pretends to come from Efax but actually comes from “service@efax.delivery” which is a look-a-like, typo-squatted or other domain that can easily be misidentified, mistaken or confused with the genuine site.

These have a malicious office file attachment. Today they are using macro enabled word docs that only fire off when an Active X control is first enabled or allowed. This then uses the Squiblydoo attack (https://www.carbonblack.com/2016/04/28/threat-advisory-squiblydoo-continues-trend-of-attackers-using-native-os-tools-to-live-off-the-land/) method to call out to a pastebin site to run an XML file which contains the embedded .exe in an encoded / encrypted format, that the macro decodes & drops.

This basically means that Trickbot is attempting to perform a partially file less malware attack where all the intermediate files are not on the victims computer, so forensic analysis and the complete is much harder to investigate.

For a recipient to actually be infected by this, you need to perform several manual steps. First save & open the word doc. Next ignore the 1st warning and allow editing. next ignore the 2nd and 3rd and subsequent warnings and allow the active X control, content and macros.

EFax has not been hacked or had their email or other servers compromised. They are not sending the emails to you. They are just innocent victims in exactly the same way as every recipient of these emails.

What has happened is that the criminals sending these have registered various domains that look like the genuine Company, Bank, Government Department or message sending service. Normally there is only one newly registered domain that imitates a well known Company, Government Department, Bank or other organisation that can easily be confused with the genuine body or website in some way. These are hosted on & send the emails from 3 or 4 different servers. Some days however we do see dozens or even hundreds of fake domains.

Today’s example of the spoofed domain is, as usual, registered via Godaddy as registrar. Because of new GDPR rules we cannot easily find the registrants name or any further details.
efax.delivery hosted on & sending emails via 85.17.147.176 | 95.211.170.194 | 95.211.163.5 | 192.162.137.144 |
You can now submit suspicious sites, emails and files via our Submissions system

Email Details

From: eFax <service@efax.delivery>
Date: Tue 19/03/2021 20:32
Subject: You have a new eFax message!
Attachment: 713-288-4192.doc

Body Content:

You have a new fax!
Logo_efax <https://www.efax.com/?utm_source=j2es&amp;utm_medium=email&amp;utm_content=logo&amp;utm_campaign=paid-inbound-fax-success&amp;j=true>
Faxing Simplified
You have a new fax from eFax! Please find attached a copy of document.
Fax Details
Caller ID:
Date Received:
Type:
Number of pages:
Reference #:
301-837-3218
2019-03-19 08:49:19 GMT
Microsoft Office
4
chd_did1-301-837-3218-301-837-3218-57
Enjoy all the benefits of eFax:
– Send faxes from your Android <https://play.google.com/store/apps/details?id=com.j2.efax&amp;referrer=utm_source%3Dpaid-fax-success%26utm_medium%3Demail> or iOS <https://itunes.apple.com/us/app/apple-store/id399922064?pt=279696&amp;ct=paid-fax-success&amp;mt=8> device
– Sign and edit faxes <https://www.efax.com/features/electronic-signature?utm_source=j2es&amp;utm_medium=email&amp;utm_term=sign-faxes&amp;utm_content=text&amp;utm_campaign=paid-inbound-fax-success&amp;j=true> with no printing required
– Send large files <https://www.efax.com/features/large-file-sharing?utm_source=j2es&amp;utm_medium=email&amp;utm_term=large-files&amp;utm_content=text&amp;utm_campaign=paid-inbound-fax-success&amp;j=true> by email (up to 3GB)
– Learn more >> <https://www.efax.com/features?utm_source=j2es&amp;utm_medium=email&amp;utm_term=learn-more&amp;utm_content=text&amp;utm_campaign=paid-inbound-fax-success&amp;j=true>
Thank you for choosing eFax!
Sincerely,
The eFax Team
P.S. Too busy to answer all your business calls? Let eVoice answer, manage and route your phone calls 24/7. Try a Free 30-Day Trial Today! <https://www.evoice.com/lp/interactive?source-id=32173&amp;utm_source=j2es&amp;utm_medium=email&amp;utm_term=evoice-free-trial&amp;utm_content=text&amp;utm_campaign=paid-inbound-fax-success&amp;j=true>
j2 <http://www.j2global.com/cloud-connect?utm_source=j2es&amp;utm_medium=email&amp;utm_content=footer&amp;utm_campaign=paid-inbound-fax-success&amp;j=true>
© 2019 j2 Global, Inc and affiliates. All rights reserved.
eFax is a registered trademark of j2 Global, Inc. and affiliates.
6922 Hollywood Blvd., Los Angeles, CA 90028
This account is subject to the terms listed in the eFax Customer Agreement <https://www.efax.com/legal?utm_source=j2es&amp;utm_medium=email&amp;utm_term=customer-agreement&amp;utm_content=text&amp;utm_campaign=paid_fax_success&amp;j=true#agreement> .

Screenshot:

Fake Efax email

Malware Details

Fake Efax Word Doc

713-288-4192.doc Current Virus total detections | Hybrid Analysis | Anyrun |
This malware doc downloads from http://pastebin.com/raw/nQ4yJ47k which is an encrypted / encoded xml file VirusTotal |

This in turn drops the trickbot executable file VirusTotal | Gtag Ser0319us
There is no alternate Download location with this delivery campaign
The folder for the files & configs is: C:\Users\[User]\AppData\Roaming\Microsoft\
This tries to download the usual table.png and radiance.png from http://213.183.63.75/ but there is no response from the site, either when using Anyrun or manually using a range of proxies.

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 spreadsheet 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, macros and DDE “exploit /Feature” and embedded ole objects 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. If the protected mode bar appears when opening the document DO NOT follow the advice they give to enable macros or enable editing to see the content. The document will have a warning message, but you will be safe.

Be aware that there are a lot of other 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 outweighing the convenience, benefits and cost of keeping an old version going.


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, embedded Oles or DDE 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

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.

IOC:
Main object- “713-288-4192.doc”
sha256 093d7065b58d12653ecd49a9c96dfa7a24b9c5224592f83ef4fa150efccc7a0b
sha1 967da912065d014c275463917d236836967b27ca
md5 61f1a99292a199f867b168b76fc8cc74
calls out to
url http://pastebin.com/raw/nQ4yJ47k
MD5 ae692be381d28d662eb6f7253cb77220
SHA-1 83c8ff09f2b057a1e57e6d2e988dc96bacada856
SHA-256 c6e92ce99784d6053ffae7325a2ea410b01846e4de9ddb69dfb8b6146cab1388
Dropped executable file
sha256 C:\Users\admin\AppData\Roaming\Microsoft\22935.exe 473f6c4cd27ceee5cd39333167623d17bb35be016fac87fcf2a6d369159e9690
MD5 d18ee627bccf269e53ba9617ee5c5fd7
SHA-1 a81ccfc4d06276674c22f0087b5ecbdac692479b
DNS requests
domain pastebin.com
domain ident.me
domain hvn7wsa62jjhkuyk.onion
domain 130.86.212.62.zen.spamhaus.org
domain 130.86.212.62.cbl.abuseat.org
Connections
ip 104.20.209.21
ip 179.189.241.254
ip 176.58.123.25
ip 185.255.79.7
ip 37.44.215.137
ip 103.119.144.250
ip 213.183.63.75
HTTP/HTTPS requests
url http://pastebin.com/raw/nQ4yJ47k
url https://ident.me/
url http://103.119.144.250:8082/ser0319us/USER-PC_W617601.5FC706E2E58655F42BFEA673E14C26F0/81/
url http://103.119.144.250:8082/ser0319us/USER-PC_W617601.5FC706E2E58655F42BFEA673E14C26F0/83/
url http://213.183.63.75/radiance.png
url http://213.183.63.75/table.png
url http://103.119.144.250:8082/ser0319us/USER-PC_W617601.5FC706E2E58655F42BFEA673E14C26F0/90
Email from:
eFax <service@efax.delivery>
85.17.147.176
95.211.170.194
95.211.163.5
192.162.137.144

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