[LACNIC/Seguridad] IoT_reaper: A Rappid Spreading New IoT Botnet
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Lun Oct 23 11:25:26 BRST 2017
IoT_reaper: A Rappid Spreading New IoT Botnet
20 October 2017 on IoT Botnet, Botnet, Mirai
On 2017-09-13 at 01:02:13, we caught a new malicious sample targeting
IoT devices. Starting from that time, this new IoT botnet family
continued to update and began to harvest vulnerable iot devices in a
The bot borrowed some code from the famous mirai botnet, but it does not
do any password crack all. Instead, it purely focuses on exploiting IoT
device vulnerabilities. So, we name it IoT_reaper.
IoT_reaper is fairly large now and is actively expanding. For example,
there are multiple C2s we are tracking, the most recently data (October
19) from just one C2 shows the number of unique active bot IP address is
more than 10k per day. While at the same time, there are millions of
potential vulnerable device IPs being queued into the c2 system waiting
to be processed by an automatic loader that injects malicious code to
the devices to expand the size of the botnet.
Currently, this botnet is still in its early stages of expansion. But
the author is actively modifying the code, which deserves our vigilance.
Here we are sharing some quick summary so the security community may
stop its before it causes bigger damage.
>From Mirai, Beyond Mirai
The botnet partially borrows some mirai source code, but is
significantly different from mirai in several key behaviors, including:
No longer crack any weak password, only exploit IoT devices
A LUA execution environment integrated, so more complex attacks can
be supported and carried out;
Scan behavior is not very aggressive, so it can stay under the radar.
Sample Delivery, C2 Distribution and Traffic Pattern
Take hxxp://18.104.22.168/sa as an example, IoT_reaper's sample
delivery and C2 distribution are as follows. There is a downloader,
quite different from Mirai:
downloader: 22.214.171.124, samples can be downloaded from this
server and it usually uses "d" as subdomain, like d.hl852.com
controller: 126.96.36.199, which can control bots, send commands
and usually uses "e" as subdomain, like e.hl852.com
reporter: 188.8.131.52, which is used to receive potentially
vulnerable device info collected by bots, it usually uses "f" as
subdomain, like f.hl852.com.
loader: 184.108.40.206, implants bot program through vulnerabilities
into devices collected by reporter
The following figures shows traffic pattern of the above 4 IPs：
9 IoT Vulnerability Exploits Integrated in the Malware
Unlike Mirai that uses weak password cracking, IoT_reaper infects IoT
devices by exploiting multiple IoT device vulnerabilities.
We noticed 9 IoT vulnerability exploits have been integrated into
current samples as follows:
Vacron NVR https://blogs.securiteam.com/index.php/archives/3445
Note just in the last 10 days, the attacker has continuously added more
new exploits into samples, one of which is adopted only 2 days after the
disclosure of the vulnerability was made.
Vacron NVR remote exploit was exposed on 2017-10-08 and was added
into bot sample before 2017-10-10;
3 and 1 exploits are added separately in two updates on 2017-10-12
The LUA Execution Environment Integrated in the Malware
Based on the integrated LUA execution environment, author will be able
to write very complex and efficient attack scripts now
Approximately 100 DNS Open Resolvers Were Integrated in This Malware
The botnet has embedded more than 100 DNS open resolvers in its lua
sample, so dns amplification attack can be easily carried out. And a
cross-checking with our DRDoS data feed indicates that about one-third
of these open DNS servers have been used as reflector in real dns
amplification attacks. We have yet to see this type of config in any
other mirai variants.
No DDoS Attack Command observed Till Now
In terms of attacking command, although we saw support of DDoS attack in
the source file of Lua execution environment, we have not seen actual
DDoS attack so far. The only instructions we saw are to download
samples. This means the attacker is still focusing on spreading the botnets.
By using some tricks, we are able to draw some fairly accurate
measurement on the scale of the infection, here are a sample of the numbers.
Number of vulnerable devices in one c2 queue waiting to be infected
: over 2m;
Infected bots controlled by one c2 in last 7 days: over 20k ;
Number of daily active bots controlled by one c2 : around 10k for
yesterday(October 19) ;
Number of simultaneous on-line bots controlled by one c2 : around 4k
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