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Tuesday, 12 May 2015

Malware spam: "ATTN: Outstanding Invoices - [4697E0] [April|May]"

This spam comes with random senders and reference numbers, but in all cases includes a malicious attachment:

From:    Debbie Barrett
Date:    12 May 2015 at 11:14
Subject:    ATTN: Outstanding Invoices - [4697E0] [April|May]

Dear anthony,

Kindly find attached our reminder and copy of the relevant invoices.
Looking forward to receive your prompt payment and thank you in advance.

Kind regards
The attachment name combines the recipient's email address with the fake reference number, e.g. barry_51DDAF.xls which isn't actually an Excel file at all, but a multipart MIME file. Payload Security's Hybrid Analysis tools manages to analyse it though, showing several steps in the infection chain.

First a VBScript is downloaded from pastebin[.]com/download.php?i=5K5YLjVu

Secondly, that VBScript then downloads a file from 92.63.88[.]87:8080/bt/get.php (MWTV, Latvia) which is saved as crypted.120.exe, this has a detection rate of 2/57.

This component then connects to 46.36.217.227 (FastVPS, Estonia) and according to this Malwr report drops a Dridex DLL with a detection rate of 3/56.

There are several different attachments, so far I have seen the following MD5s:
110B42E097A7677A993CF1B3B24743D8
20AEB9ECEBC26B3CDE960728E890F904
33A8CBE7B75B20B5EA1069E3E2A13D80
3973E29F7BDC7903FFCB596B10F9FD54
7019D711AE0E2FEDEE25EAA3341CFB7F
949816F4DF724E690690B3C8AD3871D4
9CDEFFBAC7B79302D309404E6F3068C4
B5C2393D44D8E0C94D04E2D159AE8776
B84D52F59AEC53B8D7FA109D256FCB6B
CA5E8A531A8EE24B15FC7B2A66502042
E99216D829C632DF24ECAD9162AF654C
EC1AD4316DBA799EF2E2440E715CD5F5
F4B5B0AE85F27E0A475BD359F5BE76E8
F666682D638FE67607DD189705844AD5

The MD5s for the malware components are:
DD7ADC5B140835DC22F6C95694F9C015
9AFECFAA484C66F2DD11F2D7E9DC4816
838F0A8D3FCBD0DDB2F8E8D236D17957

Recommended blocklist:
92.63.88.0/24
46.36.217.227


2 comments:

Unknown said...

We too received this yesterday, and as usual, sent out a reminder not to open any files from unknown users.

Vivek said...

Additional MD5 hashes of the xls file

64e8b85db235123adf69bdb855e50961
1281df9aae7cbed8c8fe3dae4281460e
e3148ed1e7a3b12edaec53ebbc506c66