We have been noticing a change in the malware delivery pattern with Lokibot ( and possibly other malware) over the last few days. Instead of using the more normal Excel file extensions like XLS or XLSX they have started to use .XLAM extensions.
According to Lifewire the XLAM extension is
A file with the XLAM file extension is an Excel Macro-Enabled Add-In file that’s used to add new functions to Excel. Similar to other spreadsheet file formats, XLAM files contain cells that are divided into rows and columns that can contain text, formulas, charts, images and more.
Now in theory this extension should not automatically open or any content should not automatically run on Excel. What is supposed to happen is a prompt to add the file to the excel addins appears & you should have to select the file to add it & Excel then runs the macro inside it.
From what I can see these bypass “Protected View ” in Microsoft Office
However when I ran this file through Anyrun, and Hybrid Analysis it automatically ran the macro inside the file. I don’t know what actually happens on a real computer. ( Online sandboxes will have lower security settings & have functions enabled that most stand alone computers don’t have. They are designed for researchers & company IT / security departments to run files safely & see what they are supposed to do and enable us to build protections accordingly).
It is very possible that the macro content will run silently in the background in many versions of Excel. From what I read on various forums and help sites the content inside an XLAM file will not display in an Excel spreadsheet, but it might automatically run in the background, unless added via the addins menu. Both sandbox reports show what appears to be a blank / empty worksheet.
I cannot see anyway to block these xlam files from opening or being used in Excel on a domestic computer without blocking the majority of Excel functions and the standard inbuilt Excel Addins that are supplied by Microsoft & installed automatically. There might be a way using Group Policy on Pro versions of windows, but not on home versions. All the information I can find on Microsoft relates to Office 2016. The majority of small businesses that this sort of malware is targeted at will not have full time IT support. The IT “department” is normally one of the junior staff or the owner themselves who have limited knowledge about computer security.
An email with the subject of “Confirm availability” pretending to come from “firstname.lastname@example.org” with a malicious Excel XLS spreadsheet attachment delivers Lokibot
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.
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.
This macro contains a base 64 encoded blob with all the download details
Just to note I am also seeing this Lokibot version being distributed via the Equation editor exploits in Microsoft Word using malformed RTF files.
This malware doc file downloads from http://bit.ly/2CFTQjM which redirects to https://a.doko.moe/owzvfh.hta ( VirusTotal) which in turn downloads https://a.doko.moe/kdklym.jpg Which is a renamed .exe file VirusTotal |
The C2 is http://hiox.flu.cc/209tsn/fred.php
You can now submit suspicious sites, emails and files via our Submissions system
None of the alleged senders in these emails have 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. All the emails are coming via a compromised or fraudulently set up server or hosting account on 126.96.36.199
The email looks like:
Date: Fri 26/10/2018 12:15
Subject: Confirm availability
Dear, One of your customer directed us to contact you regarding this product as attached below. We will like to have more details regarding the enclose product sampleand also send us price list of attached product. Await your quick response. Ahmed Abdullah Purchase Manager,Kohyei Trading Co.,LtdTel.: 095 2481775, 248118. Mobile: 0095 99002, Fax: 0065 24837Email: email@example.comWeb: www.dbsocolwed.com
The second email with RTF Doc file looks like:
Date: Fri 26/10/2018 12:15
Subject: Re: Re: Re: SCA Quotation
Hello dear Good day, Kindly find the attached quotation as requested, please note prices are going up and price can change at any time. check the attached at earliest and revert back to us Your prompt reply is highly appreciated. Thanks in advance. Best Regards, Jovin Amed Purchase Manager,Xin’an Import & Export Co., Ltd16th Floor, Sobha Sapphire, Al Khail roadTel.: 095 2481775, 248118. Fax: 0065 24837Email: firstname.lastname@example.org /email@example.comWeb: www.dbsocolwed.com
|188.8.131.52||acoler.776496.com||US||AS49004 SquareFlow Communications Limited|
Received: from [184.108.40.206] (port=41608 helo=ninh24.com) by my email server with esmtp (Exim 4.91) (envelope-from <firstname.lastname@example.org>) id 1gGCO5-0007ej-V9 for email@example.com; Sat, 27 Oct 2018 01:23:34 +0100 Received: from 220.127.116.11 (localhost [IPv6:::1]) by ninh24.com (Postfix) with ESMTPA id 5694A10DCBF; Fri, 26 Oct 2018 10:37:13 +0000 (UTC) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=_715b78a64c27c147da64bad239ae31f8" Date: Fri, 26 Oct 2018 03:37:13 -0700 From: firstname.lastname@example.org To: undisclosed-recipients:; Subject: Re: Re: Re: SCA Quotation Message-ID: <email@example.com> X-Sender: firstname.lastname@example.org User-Agent: Roundcube Webmail/1.0.4
Received: from [18.104.22.168] (port=37440 helo=ninh24.com) by my email server with esmtp (Exim 4.91) (envelope-from <email@example.com>) id 1gGDfO-0003lh-R3 for firstname.lastname@example.org; Sat, 27 Oct 2018 02:45:31 +0100 Received: from 22.214.171.124 (localhost [IPv6:::1]) by ninh24.com (Postfix) with ESMTPA id 0C588111734; Fri, 26 Oct 2018 11:15:29 +0000 (UTC) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=_669812266ea58ea22c5d684e3a19bd18" Date: Fri, 26 Oct 2018 04:15:28 -0700 From: email@example.com To: undisclosed-recipients:; Subject: Confirm availability Message-ID: <firstname.lastname@example.org> X-Sender: email@example.com User-Agent: Roundcube Webmail/1.0.4
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 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 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 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.
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 firstname.lastname@example.org.
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.
Email from: email@example.com