Malware spam: "The Insolvency Service" / "Investigations Inquiry Notification" / chucktowncheckin.com / chapelnash.com

This malware spam in unusual in many respects. The payload may be some sort of ransomware [UPDATE: this appears to be Cerber].

From: The Insolvency Service [mailto:service@chucktowncheckin.com]
Sent: 19 January 2017 12:22
Subject: EGY 318NHAR12 - Investigations Inquiry Notification



Company Investigations Inquiry
Informing You that we have received appeal regarding your company which indicates corporate misconduct.
Your Inquiry Number: 84725UPTN583
As part of this occasion we have made our own background investigation and if it occurs to be in the public interest, we can apply to the court to wind up the company and stop it trading.
Also if the performance of the director(s) who run the company is questionable enough, we can commence proceedings to disqualify them from governing a limited company for a time span up to 15 years.
FURTHER CASE DATA
The investigation can give us information that we can transmit to another regulatory body that has more suitable powers to deal with any concerns the investigation uncovers.
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Sample subjects are:

LSV 354EMPU31 -  Investigations Inquiry Reminder
JXI 647TESR39 -  Investigations Inquiry Reminder
SHV 622WYXP68 -  Investigations Inquiry Notice
QPY 661APWZ41 -  Investigations Inquiry Notice
FHF 338SYBV85 -  Investigations Inquiry Notice
EGY 318NHAR12 -  Investigations Inquiry Notification
IZJ 296CNWP92 -  Investigations Inquiry Notice

All the senders I have seen come from the chucktowncheckin.com domain. Furthermore, all of the sending servers are in the same /24:

194.87.216.87
194.87.216.62
194.87.216.40
194.87.216.43
194.87.216.3
194.87.216.7
194.87.216.80

All the servers have names like kvm42.chapelnash.com in a network block controlled by Reg.ru in Russia.

The link in the email goes to some hacked WordPress site or other, then ends up on a subdomain of uk-insolvencydirect.com e.g. 2vo4.uk-insolvencydirect.com/sending_data/in_cgi/bbwp/cases/Inquiry.php - this is a pretty convincing looking page spoofing the UK government, asking for a CAPTCHA to download the files:

Entering the CAPTCHA downloads a ZIP file (e.g. 3d6Zy.zip) containing a malicious Javascript (e.g. Inquiry Details.js) that looks like this [Pastebin].

Hybrid Analysis of the script is rather interesting, not least because it performs NSLOOKUPs against OpenDNS servers (which is a really weird thing to do give that OpenDNS is a security tool).

The script downloads a component from www.studiolegaleabbruzzese.com/wp-content/plugins/urxwhbnw3ez/flight_4832.pdf and then drops an EXE with an MD5 of e403129a69b5dcfff95362738ce8f241 and a detection rate of 5/53.

Narrowing the Hybrid Analysis down to just the dropped EXE, we can see these peculiar OpenDNS requests as the malware tries to reach out to:

soumakereceivedthiswith.ru (176.98.52.157 - FLP Sidorenko Aleksandr Aleksandrovich, Russia)
sectionpermiathefor.ru (151.0.42.255 - Online Technologies, Ukraine)
programuserandussource.ru (does not resolve)
maytermsmodiall.ru (does not resolve)

It isn't exactly clear what the malware does, but you can bet it is Nothing Good™.

I recommend that you block email traffic from:

194.87.216.0/24

and block web traffic to

uk-insolvencydirect.com
studiolegaleabbruzzese.com
176.98.52.157
151.0.42.255