Red Lion Controls Sixnet RTU Exposed Dangerous Method Or Function
When user authentication is not enabled the shell can execute commands with the highest privileges. Red Lion SixTRAK and VersaTRAK Series RTUs with authenticated users enabled (UDR-A) any Sixnet UDR message will meet an authentication challenge over UDP/IP. When the same message comes over TCP/IP the RTU will simply accept the message with no authentication challenge.
Description: CWE-749 Exposed Dangerous Method Or Function
Metrics
Version
Base score
Base severity
Vector
3.1
10.0
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Version:3.1
Base score:10.0
Base severity: CRITICAL
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Metrics Other Info
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CAPEC ID
Description
Solutions
Red Lion recommends users apply the latest patches https://support.redlion.net/hc/en-us/articles/19338927539981-SixTRAK-and-VersaTRAK-Security-Patch-RLCSIM-2023-05 to their products.
Red Lion recommends users apply additional mitigations to help reduce the risk:
* Enable user authentication, see Red Lion instructions https://support.redlion.net/hc/en-us/articles/18190385510797-ACCESS-RTU-and-IO-How-to-install-a-patch-or-package-to-the-RTU .
Blocking all or most Sixnet UDR messages over TCP/IP will eliminate authentication bypass. Sixnet UDR messages over TCP/IP will be ignored.
To block all Sixnet UDR messages over TCP/IP install Patch1_tcp_udr_all_blocked.tar.gz.
* ST-IPm-8460 – Install 8313_patch1_tcp_udr_all_blocked.tar.gz
* ST-IPm-6350/VT-mIPm-245-D/VT-mIPm-135-D/VT-IPm2m-213-D/VT-IPm2m-113-D – Install 855_patch1_tcp_udr_all_blocked.tar.gz
To block all Sixnet UDR messages except I/O commands over TCP/IP and UDP/IP install Patch2_io_open.tar.gz.
* ST-IPm-8460 – Install 8313_patch2_io_open.tar.gz
* ST-IPm-6350/VT-mIPm-245-D/VT-mIPm-135-D/VT-IPm2m-213-D/VT-IPm2m-113-D – Install 855_patch2_io_open.tar.gz
To Block all Sixnet UDR messages over TCP/IP:
* Enable iptables rules to block TCP/IP traffic.
* In the Sixnet I/O Tool Kit go to Configuration>Configuration Station/Module>"Ports" tab>Security.
* Select the "Load the this file with each station load" radio button to load a custom rc.firewall configuration file. The rules below will allow all other traffic except Sixnet UDR over TCP/IP. Please Note: Two rules that are added in by default were removed because they will block all traffic going into the interface.
Remove these rules from the default rc.firewall file:
* iptables -P INPUT DROP (Drops everything coming in)
* iptables -P FORWARD DROP (Drops everything in FORWARD chain)
Add one DROP rule which will drop all TCP/IP packet coming on UDR port 1594 by typing the following commands:
* insmodip_tables (Initialization)
* insmodiptable_filter (Initialization)
* insmodip_conntrack (Initialization)
* insmodiptable_nat (Initialization)
* iptables -F INPUT (Flushes INPUT chain)
* iptables -F OUTPUT (Flushes OUTPUT chain)
* iptables -F FORWARD (Flushes FORWARD chain)
* iptables -Z (Zero counters)
* iptables -P OUTPUT ACCEPT (Drops everything coming in, everything in FORWARD chain, and accepts everything going out)
* iptables -A INPUT -p tcp --dport 1594 -j DROP (Allows local traffic and blocks all TCP traffic coming from 1594)
For installation instructions see Red Lion's support page https://support.redlion.net/hc/en-us/articles/18190385510797-ACCESS-RTU-and-IO-How-to-install-a-patch-or-package-to-the-RTU .
For more information, please refer to Red Lion’s security bulletin https://support.redlion.net/hc/en-us/articles/19339209248269-RLCSIM-2023-05-Authentication-Bypass-and-Remote-Code-Execution .
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Credits
finder
Nitsan Litov of Claroty Research - Team82 reported these vulnerabilities to CISA.