Re: Over 135 million modems vulnerable to denial-of-service flaw

[Anonymous Remailer (austria)]

In article <c8854324eae8e897...@anemone.mooo.com>
Jeremy Bentham <nob...@anemone.mooo.com> wrote:
>
> http://www.zdnet.com/article/millions-of-routers-vulnerable-to-unpatched-reboot-flaw/

That zdnet article is erroneous and inaccurate.

Resetting those cable modems does nothing but cause them to
reboot and reload a config file.

BUT, an attacker has to be ON a PRIVATE RFC 1918 network,
inaccessible from the Internet in ALL cases.

They would also have to connect to each modem in order to
accomplish said feat. It would take a very long time to scan
the entire address space and find any modems in it.

Article grade, D--.

[Cornelis Tromp]

According to your critique, Article grade, F-.

[Bit Twister]

On Mon, 11 Apr 2016 12:10:23 +0200 (CEST), Anonymous Remailer (austria) wrote:
>
> In article <c8854324eae8e897...@anemone.mooo.com>
> Jeremy Bentham <nob...@anemone.mooo.com> wrote:
>>
>> http://www.zdnet.com/article/millions-of-routers-vulnerable-to-unpatched-reboot-flaw/
>
> That zdnet article is erroneous and inaccurate.

> Resetting those cable modems does nothing but cause them to
> reboot and reload a config file.

But if that config file contents were reset to factory defaults it
might not connect to the ISP provider.

> BUT, an attacker has to be ON a PRIVATE RFC 1918 network,
> inaccessible from the Internet in ALL cases.

But you do not understand the exploit. As far as the modem is
concerned it saw the reset from the user on the LAN.

> They would also have to connect to each modem in order to
> accomplish said feat.

They don't have to. The user gets it when looking at an infected web page.
As the article indicated it is a LAN side exploit.

> It would take a very long time to scan
> the entire address space and find any modems in it.

Just how many users do you think get into their modem and change the
LAN gateway address.

The address and web page is hard coded for that modem. See
http://192.168.100.1/cmConfigData.htm?BUTTON_INPUT1=Reset+All+Defaults

[Fritz Wuehler]

In article <slrnngnbq4.o...@wb.home.test>

Bit Twister <BitTw...@mouse-potato.com> wrote:
>
> On Mon, 11 Apr 2016 12:10:23 +0200 (CEST), Anonymous Remailer (austria) wrote:
> >
> > In article <c8854324eae8e897...@anemone.mooo.com>
> > Jeremy Bentham <nob...@anemone.mooo.com> wrote:
> >>
> >> http://www.zdnet.com/article/millions-of-routers-vulnerable-to-unpatched-reboot-flaw/
> >
> > That zdnet article is erroneous and inaccurate.
>
> > Resetting those cable modems does nothing but cause them to
> > reboot and reload a config file.
>
> But if that config file contents were reset to factory defaults it
> might not connect to the ISP provider.

A user can reset the modem and erase every setting in it a
thousand times a day, matters naught. It will resume correct
operation every single time when it gets an IP address assigned
to it and the bootp config file is delivered. A user cannot
reset the contents of the modem bootp config file provided by
the provider DHCP server. Every type of modem has a specfic
bootp config file.

>
> > BUT, an attacker has to be ON a PRIVATE RFC 1918 network,
> > inaccessible from the Internet in ALL cases.
>
> But you do not understand the exploit. As far as the modem is
> concerned it saw the reset from the user on the LAN.

What exploit? It's not an "exploit". It was intentionally
designed that way.

> > They would also have to connect to each modem in order to
> > accomplish said feat.
>
> They don't have to. The user gets it when looking at an infected web page.

Yeah...? And you're going to get all the existing SB6141 modem
owners to access that webpage how?

> As the article indicated it is a LAN side exploit.

Therefore impossible to execute directly from the WAN side.

> > It would take a very long time to scan
> > the entire address space and find any modems in it.
>
> Just how many users do you think get into their modem and change the
> LAN gateway address.

None, because they can't change it.

> The address and web page is hard coded for that modem. See
> http://192.168.100.1/cmConfigData.htm?BUTTON_INPUT1=Reset+All+Defaults

Irrelevant since the modem is bridging a public address and
gateway to whatever is connected on the other side of it in the
LAN anyway.