Icom IC-9700 hidden telnet service

My Icom IC-9700 is connected to the network. And, as a freelance linux and infrastructure (security) engineer, I could not resist to do a port-scan on the box. The first result was port 23, used for the legacy telnet service. Loggin in was easy. No username and password required to get a shell. Quite shocking and a real security risk for devices directly connected to the Internet. That’s a receipe to get hacked within hours.

Since the # would suggest it’s a rootshell, the available commands are quite limited (yet…). But I assume it’s an RTOS shell. I’ll find time to figure it out.


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    • dave on 05/04/2019 at 23:32
    • Reply

    Wow! That’s pretty bass-ackward on Icom’s part. I’m not sure what could be hacked (besides a restart or a password change) unless there are hidden commands…

    • Jeff Hochberg on 06/04/2019 at 18:42
    • Reply

    Any authentication required? Or just telnet to port 23 and you’re in?

    1. No auth.

    • Torque on 09/04/2019 at 13:47
    • Reply

    Never open firewall ports to your radio, always use a VPN instead. (No matter what other fools tell you).

    • Ed Woodrick on 14/04/2019 at 20:20
    • Reply

    Why would anyone ever directly connect the radio to the Internet? It should always be behind a firewall with only the specifically required ports opened.

    • David on 05/05/2019 at 10:30
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    Second page of the manual says:

    “This product includes RTOS “RTX” software, and is
    licensed according to the software license.

    This product includes “zlib” open source software,
    and is licensed according to the open source
    software license.

    This product includes “libpng” open source software,
    and is licensed according to the open source
    software license.

    Refer to the “About the Licenses” page at the end
    of this manual for information on the open source
    software being used in this product.”

    So yes, RTOS RTX.

    • Some User on 14/04/2020 at 23:53
    • Reply

    Good grief. Just because it answers on port 23 doesn’t mean it’s a security problem, and just because the prompt is # doesn’t mean it’s a “root shell.” It obviously isn’t. The interface appears to be extremely limited.

  1. Hi, I’m also digging on that, I found this backdoor because I was trying to investigate why I can’t connecto to the UDP ports for Remote connection, perhaps they are not opne on the router.

    • Jon Gefaell on 08/03/2021 at 00:59
    • Reply

    This is certainly concerning. However, I would suggest you don’t forward TCP:23 through your NAT/PAT, or allow it to pass your firewall. It doesn’t overly bother me because of that. and WTF is that on TCP:1111?

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