compromised windstream email sending malspam

Got a bit of a dodgy one here today, where it looks like the email service for windstream.net has been compromised to allow a miscreant to send malicious emails that are passing all authentication.

It is highly likely that it is an individual customer of Windstream that has been compromised, rather than the entire system, but the whole idea of a company outsourcing mailing services to a 3rd party like Zimbra / Synacor is their filtering systems that is supposed to detect & block malware, spam and other malicious content

Windstream are a major US ISP / Telecoms  company  / entertainment services provider all over the USA with hundreds of thousands if not millions of customers, both domestic and commercial.

The email is nothing special but due to passing all authentication stands a higher change of passing through spam and malware filters and being delivered to recipients. This email also attempts to bypass malware and content filters by having the malicious content inside a zip file which is inside another zip file.

As you can see from the email headers the emails actually come via an  mailing service syn-alias.com owned by Synacor using Zimbra mailing system  which is used by numerous large corporations worldwide  for mass mailings and mail services.

This malicious file is a pony/fareit Trojan, the c2 & download of additional malware appears to have been blocked by the hosting company and is returning a 404 error. However  it is quite common for Pony / Fareit to return 404 errors but still perform malicious acts.

I could not get this to run in a Windows 7 sandbox on Anyrun only a windows 10 sandbox / VM

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

Company Quotation-PO.zip ( virusTotal) : Extracts to:  AZ-QUOTATION-PO.zip which in turn extracts to    AZ-QUOTATION-PO.exe        Current Virus total detectionsAnyrun App |

The C2 for this is http://chisom.j.pl/only/gate.php

it attempts to download  http://chisom.j.pl/only/waka.exe which gives a 404  not found error. I have no way of knowing if this is a genuine 404 and the hosting company has removed the files  or as is typical with pony / fareit is a “fake” error

One of the  emails looks like:

From: Sales <This email address is being protected from spambots. You need JavaScript enabled to view it.>

Date: Thu 06/06/2019 23:09

Subject: Order Inquiry

Attachment: Company Quotation-PO.zip

Body content:

Good Day,

Here is the product required by my customer

Please attached is the purchase order,

check and get back to me with prices and payment Terms.

Thanks Regards,

AL-JABER GROUP LTD

Head Office

1120, Al Muthaf St, Doha Qatar.

PO Box 1826,

Tel: (00974) 48022003

Mob: +974 6622 6754

Screenshot:

Fake Order Email

Fake Order Email

Email Headers:

IP Hostname City Region Country Organisation
69.168.106.36  mail.windstream.syn-alias.com Buffalo New York US AS36271 Synacor, Inc.
167.88.12.229  229-12-88-167.reverse-dns West Chicago Illinois US AS20278 Nexeon Technologies, Inc.

Note: Only the final IP address outside of your network in the Received: fields can be trusted as others can be spoofed

Received: from mail.windstream.syn-alias.com ([69.168.106.36]:22551 helo=mail.windstream.net)
	by my email server with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256)
	(Exim 4.92)
	(envelope-from <This email address is being protected from spambots. You need JavaScript enabled to view it.>)
	id 1hZ0ZJ-00054i-0g
	for This email address is being protected from spambots. You need JavaScript enabled to view it.; Thu, 06 Jun 2019 23:09:10 +0100
DKIM-Signature: v=1; a=rsa-sha1; d=windstream.net; s=20180222; c=relaxed/simple;
	q=dns/txt; i=@windstream.net; t=1559858948;
	h=From:Subject:Date:To:MIME-Version:Content-Type;
	bh=mElS+Ov0taa7OWrEJZMdoW4HBaY=;
	b=mtjRkUifs7uqjGMfv5hQWzXJAjeUTSTemFJ9BzAUo013BMLaUaBnpQxDWW761CM5
	TLFicvk2rHx30mVJhy2xh/EaDoN9p+cyaxgWKV+rYfTbDxmfC6h1G9ZTZMf/laWF
	2B8giWCrf4+Bo1LjY7irejaVw0vO7Lj5TWPCMCpyVVjscH1U6GOZAItg9mfgPg1x
	+lMKhnQ04JlR2iaU9wmpu3y3HPTTYgTsOYjva4ZubRnMs81zy0CwDXj771YdJAQ/
	cKf4C58nm3IfifKf6hJMjaEQEX0mFaxghyd8c+aWdcJhsqUCRL3xOWeh/6YwpUhs
	BIfI0ZcYVwyKxwyjuqLn2Q==;
X_CMAE_Category: , ,
X-CNFS-Analysis: v=2.2 cv=EoeQlmUA c=1 sm=1 tr=0 a=lshYrInN7gf8t1I3izzuCA==:117 a=lshYrInN7gf8t1I3izzuCA==:17 a=KGjhK52YXX0A:10 a=dq6fvYVFJ5YA:10 a=Cnp5Re-8buoA:10 a=KXl77lDgDEgIEtoqJYcA:9 a=dZRlXA5CJXLToV4ITPYA:9 a=wPNLvfGTeEIA:10 a=RSsPyB7hMuXjlfKTBmgA:9 a=IKIoO-ieCDEA:10 a=Yy2xoct6d_2ZlxTvqP-Z:22 a=y3gxJGGnbrtUV2GOxcvc:22
X-CM-Score: 0
X-Scanned-by: Cloudmark Authority Engine
X-Authed-Username: anNjdXN0b21Ad2luZHN0cmVhbS5uZXQ=
Authentication-Results:  smtp01.aqua.bos.sync.lan smtp.user=This email address is being protected from spambots. You need JavaScript enabled to view it.; auth=pass (LOGIN)
Received: from [167.88.12.229] ([167.88.12.229:57571] helo=[10.8.8.60])
	by mail.windstream.net (envelope-from <This email address is being protected from spambots. You need JavaScript enabled to view it.>)
	(ecelerity 3.6.25.56547 r(Core:3.6.25.0)) with ESMTPSA (cipher=DHE-RSA-AES256-SHA) 
	id 25/37-04520-6FE89FC5; Thu, 06 Jun 2019 18:09:03 -0400
Content-Type: multipart/mixed; boundary="===============0468448523=="
Message-ID: <This email address is being protected from spambots. You need JavaScript enabled to view it.>
MIME-Version: 1.0
Subject: Order Inquiry
To: Recipients <This email address is being protected from spambots. You need JavaScript enabled to view it.>
From: "Sales" <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Date: Thu, 06 Jun 2019 15:08:38 -0700
Screenshot from mailserver

Screenshot from mailserver

 

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.

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.

:

IOC:

Main object- “AZ-QUOTATION-PO.exe”sha256 a694c119fd410c7d21c164cd2244d60db196d6c2182e736190e32e0cc7f1a945sha1 fcb9e6e9fb813352c3c85e90485112174f5450c0md5 9e8475dcb9b2c2683ad6f710dcca360eDNS requestsdomain chisom.j.plConnectionsip 81.171.31.232HTTP/HTTPS requestsurl http://chisom.j.pl/only/gate.phpurl http://chisom.j.pl/only/waka.exe

Read more https://myonlinesecurity.co.uk/compromised-windstream-email-sending-malspam/

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