Malware spam: Copy of Invoice 20161802-12345678 leads to Locky ransomware

This fake financial spam spoofs different senders and different companies, with a different reference number in each.

From:    Devon Vincent
Date:    18 February 2016 at 08:14
Subject:    Copy of Invoice 20161802-99813731

Dear [redacted],

Please find attached Invoice 20161802-99813731 for your attention.

For Pricing or other general enquiries please contact your local Sales Team.

Yours Faithfully,

Devon Vincent
Tenet Healthcare Corporation    www.tenethealth.com

=================

From:    Elvia Saunders
Date:    18 February 2016 at 09:19
Subject:    Copy of Invoice 20161802-48538491

Dear [redacted],

Please find attached Invoice 20161802-48538491 for your attention.

For Pricing or other general enquiries please contact your local Sales Team.

Yours Faithfully,

Elvia Saunders
The PNC Financial Services Group, Inc.  www.pnc.com

I have seen two variants of the document (VirusTotal [1] [2]). Analysis of the documents is pending, however it is likely to be the Dridex banking trojan.

UPDATE 1

There is a second variant of the spam with essentially the same (undefined) payload:

From:    Heather Ewing
Date:    18 February 2016 at 08:41
Subject:    Invoice

Dear Sir/Madam,

I trust this email finds you well,

Please see attached file regarding clients recent bill. Should you need further assistances lease feel free to email us.

Best Regards,

Heather Ewing
The Bank of New York Mellon Corporation www.bnymellon.com

In this case the attachment was named Invoice51633050.doc - automated analysis is inconclusive. An examination of the XML attachment [pastebin] indicates that it may be malformed.

UPDATE 2

A contact (thank you) analysed one of the samples and found that the document downloaded an executable from:

killerjeff.free.fr/2/2.exe

According to this Malwr report this is the Locky ransomware, and it phones home to:

95.181.171.58 (QWARTA LLC, Russia)
69.195.129.70 (Joes Data Center, US)

I suspect that the second one may be a sinkhole, but there should be no ill effects from blocking it.


UPDATE 3

A couple more samples have come to light [1] [2] one of which shows a new phone home location of:

185.14.30.97 (ITL Serverius, NL)

UPDATE 4

From user Ralf9000 at VirusTotal here are some more download locations:

onigirigohan.web.fc2.com/1/1.exe
killerjeff.free.fr/2/2.exe
uponor.otistores.com/3/3.exe
premium34.tmweb.ru/4/4.exe
bebikiask.bc00.info/5/5.exe
avp-mech.ru/7/7.exe

6.exe seems to be missing. Analysis of these is pending.

UPDATE 5

According to these Malwr reports on all the available samples [1] [2] [3] [4] [5] [6] the various versions of Locky seem to call back to:


95.181.171.58 (QWARTA LLC, Russia)
31.41.47.37 (Relink Ltd, Russia)
185.14.30.97 (ITL, Ukraine / Serverius, Netherlands)
69.195.129.70 (Joes Datacenter, US)

I have omitted what appear to be obvious sinkholes.

Recommended blocklist:
95.181.171.58
31.41.47.37
185.14.30.97
69.195.129.70