Fake Payment Receipt Delivers Nanocore RAT Malware

Fake Payment Receipt Delivers Nanocore RAT Malware

We frequently see this sort of generic Malicious Spam email with an office file attachment that acts as a downloader for all sorts of malware. Today’s example is an email with the subject of [Your Email Address] RE:Payment Receipt for your reference!! pretending to come from Tengku Aishah <suntrade@fareast.net.th> with a malicious Excel XLS spreadsheet attachment delivers Nanocore RAT

I don’t normally bother with posting all of them and normally just tweet about them to a group of researchers. However today’s version is slightly different to the run of the mill ones. Generally we see this type of email using Word docs involving equation editor exploits particularly CVE 2017-11882 or macros. Excel spreadsheets have been used in the past but not as frequently, although this week the current trend is for almost all office type malware attachments to be Excel files not word docs.

This particular email scam tries to make it look more legitimate by adding the recipient’s email address to the subject line.

A Payment Receipt in an email would normally be either a PDF or a Word doc, not an Excel spreadsheet.
Note: The majority of receipts or Order Confirmations or similar, unless you have just ordered something will be a malicious scam designed to steal from you in some way.

If you do not recognize the company sending the receipt or order confirmation, then DO NOT open the attachment. Even if you do recognize the company and it is a company that you regularly deal with, be very cautious and don’t immediately open it. Save the attachment to a safe place on your computer, scan it with your Anti-Virus. If that does not detect anything then upload the file to Virus Total & scan it to see how many of the 60+ antiviruses detect it. If nothing detects it, still don’t assume it is safe. although it is not very common for absolutely nothing to detect it, there are enough examples of new undiscovered malware spreading.

If you are not expecting the email with the attachment then don’t open it

Remember many email clients, 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 work so well.

You can now submit suspicious sites, emails and files via our Submissions system

None of the companies appearing to send these emails 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. While some of these companies do exist, a lot are just invented by the scammers trying to infect you. In this particular example the web address does exist but is not responding. The criminals sending this scam have simply spoofed the email address and are sending them from a totally different server.

The email looks like:
From: Tengku Aishah <suntrade@fareast.net.th>
Date: Wed 21/11/2021 04:03
Subject: accounts@victimsdomain.com RE:Payment Receipt for your reference!!
Attachment: Payment Slip-21st-11-18.xlsx

Body Content:

Hello Dear,
Sorry for the delay this is the scan copy of proof of payment and
send us the new account in which we will make the remaining balance payment to.
Best regards
Indra. ramdani

Payment Slip-21st-11-18.xlsx     Current Virus total detections: Anyrun |
This malware downloads from http://heirloomsindia.net/gae/br.exe ( VirusTotal)
Note there is an open directory on this compromised webspace, where other sub directories contain additional malware
http://heirloomsindia.net/dee/uu.exe VirusTotal | Anyrun |

Email Headers:

IP Hostname City Region Country Organisation
51.254.83.74  Clansayes Rhone-Alpes FR AS16276 OVH SAS

 

Received: from [51.254.83.74] (port=51855 helo=fareast.net.th)
	by my mail server with esmtp (Exim 4.91)
	(envelope-from <suntrade@fareast.net.th>)
	id 1gPJjK-0008KE-UL
	for accounts@victimsdomain.com; Wed, 21 Nov 2021 04:03:11 +0000
Reply-To: Email ADMIN  <frankdereck3601@gmail.com>
From: Tengku Aishah <suntrade@fareast.net.th>
To: accounts@victimsdomain.com
Subject: accounts@victimsdomain.com RE:Payment Receipt for your reference!!
Date: 21 Nov 2021 05:03:20 +0100
Message-ID: <20181121050320.F2001C85F4579984@fareast.net.th>
MIME-Version: 1.0
Content-Type: multipart/mixed;
	boundary="----=_NextPart_000_0012_A95ECEBF.B42429B9"

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.

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 is enabled and macros are disabled, UNLESS you or your company have enabled them. If protected view mode is turned off and macros are enabled then opening this malicious excel spreadsheet 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 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 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” 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 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” 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.

IOC:
Payment Slip-21st-11-18.xlsx
MD5: 2f9897b1b333a308e4b42b49b4159f01
SHA-1: 472d692cdd4a78aaf3e5abf55c49c44eec5076c3
Download URLs
http://heirloomsindia.net/gae/br.exe
MD5: e87a93665298d4a41fc86b6caf5c3280
SHA1: 95b3f19da5fd8d9f71c22e495a593bf90d9676b3
http://heirloomsindia.net/dee/uu.exe
MD5: 4c7ed2a2084ad201c90eb6b055d7045d
SHA-1: 43a648c900ecf3ac84d4cbb8445bfeaace7e6fb9
192.185.143.150

Derek

Derek