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Thursday, 11 May 2017

Malware spam with "nm.pdf" attachment

Currently underway is a malicious spam run with various subjects, for example:


Senders are random, and there is no body text. In all cases there is a PDF attached named nm.pdf with an MD5 of D4690177C76B5E86FBD9D6B8E8EE23ED or 6B305C5B59C235122FD8049B1C4C794D (and possibly more). Detection rates at VirusTotal are moderate [1] [2].

The PDF file contains an embedded Word .docm macro document. Hybrid Analysis [3] [4] is partly successful, but it shows a run-time error for the malicious code, but it does demonstrate that malicious .docm file is dropped with a detection rate of 15/58.

Putting the .docm file back into Hybrid Analysis and Malwr [5] [6] shows the same sort of results, namely a download from:


Given that this seems to be coming from the Necurs botnet, this is probably Locky or Dridex.


A contact pointed out this Hybrid Analysis which looks like basically the same thing, only in this sample the download seems to work. Note the references to "jaff" in the report, which matches this Tweet about something called "Jaff ransomware".

That report also gives two other locations to look out for:


This currently gives a recommended blocklist of:

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