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UPDATED x1: Mirai Scanning for Port 6789 Looking for New Victims / Now hitting tcp/23231

Published: 2016-12-19
Last Updated: 2016-12-21 16:29:31 UTC
by John Bambenek (Version: 2)
5 comment(s)

Early today, a reader reported they were seeing a big spike to inbound tcp/6789 to their honeypots. We have seen similar on DShield's data started on December 17.  It was actually a subject of discussion this weekend and this helpful data from Qihoo's Network Security Research lab attributes the large increase to Mirai, the default-password-compromising malware infected various IoT devices that are internet-connected.  It's hard to see in the graph as it is still not a huge (but still it is significant) portion of Mirai scanning traffic. Here is port-specific graphs from Qihoo as well showing the start time of the spike.  The command the it tries to execute once logged in is:

"`busybox telnetd -p 19058 -l /bin/sh`"

Current intelligence suggests this is an attempt to compromise DaHua devices and establishes a reverse shell on port 19508 if the compromise is successful.  The usual defenses apply here (keep this stuff off the public internet, manufacturer's please stop shipping devices with telnet and default passwords) but the amount of potential bandwidth Mirai operators have under their control could potentially swamp even the most robust DDoS defenses. 

Let us know if you see other interesting behavior and feel free to update your honeypots to capture some of the attack code if you can.

UPDATE 21 Dec 2016 @ 1623 UTC: In the last 24 hours another shift has been detected now going after port 23231.

--
John Bambenek
bambenek \at\ gmail /dot/ com
Fidelis Cybersecurity

Keywords: ddos mirai
5 comment(s)
ISC Stormcast For Monday, December 19th 2016 https://isc.sans.edu/podcastdetail.html?id=5297
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