Please Check The Information Malspam Tries To Deliver Trickbot Banking Trojan

Trojan

The next in the never ending series of Malware downloaders is an email with the subject of  Please check the information-3878358  ( random numbers)  pretending to come from random names at your own email domain that tries to deliver Trickbot banking Trojan.

The site they are using to download the malware appears to be down at time of posting. Please read this post about a concurrent malspam run delivering or trying to deliver Trickbot banking Trojan.  It looks like Trickbot are also changing their delivery method. Previously we have only seen macro enabled word docs as the delivery method. Today’s attempt at using .JS files inside a zip  is a change for them and brings them into line with other major malware distribution gangs.

tessaban.com  61.19.247.54 has been used for malware spreading for some time now and really needs blocking [1] [2]  [3 ] [4 ] It looks like it was / is originally a genuine site ( a landing page for some sort of Thai Government employees union or staff organisation )  that has been  continually hacked /compromised  We first saw this site being used to spread malware  on 28 October 2016

This site has been reported to Thai cert who emailed me this morning (04.44 UTC)  to say it has been allegedly cleaned up. At time of posting I am getting a 404 from the malware link. Whether this is a total and complete clear up or whether it is just these files that have been removed and the vulnerability that exists that allowed and will continue to allow malware spreading from this domain is open to debate at this time. It is normally quite trivial to remove malware files etc. from compromised servers. It is a lot harder to track down & fix the vulnerabilities that allowed them to be used in the first place. Unfortunately it is so common to see a compromised website cleaned up and a few hours or days later the same site resumes its malware spreading role. I suspect the underlying  compromise is still there because this url ‘http://www.tessaban.com/admin/images/’ has a “dubious” source code referring to a different website.

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.

17 November  2016 :  invoice_2222.zip : Extracts to: invoice_1711.js   Current Virus total detections:  MALWR shows an attempted  download of  a file from  ‘http://www.tessaban.com/admin/images/ospspps.png’   currently giving a 404 not found which should be renamed  renamed by the script to a .exe file. 

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.

One of the  emails looks like:

From: Brigitte Guidry <Brigitte.Guidry@victim domain.tld >

Date: Thu 17/11/2016 02:48

Subject: Please check the information-3878358

Attachment: invoice_2222.zip

Body content:

Hi,

 

I have attached an invoice-4654 for you.

 

Regards,

Brigitte Guidry

Screenshot:

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.

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.

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.