Mailing List Archive: simulate connection with netcat

simulate connection with netcat

Jan 15, 2011, 12:19 PM

Post #1 of 7 (5898 views)

Hello,

my long-term intention is to write a cross-platform GUI-authpf-client
without using libssh or libssh2. Before I get into that I'd like to simulate
the ssh-connection/authentication via netcat.
I took a look at the RFCs but don't get it working.

% nc 127.0.0.1 22
SSH-2.0-OpenSSH_5.2
SSH-2.0-OpenSSH_5.2 <-- entered by me
... a lot of text ...

What do I enter now to authenticate?
My attempts resulted in "Packet corrupt".

regards,
jake

Re: simulate connection with netcat [ In reply to ]

sfandino at yahoo

Jan 17, 2011, 9:43 AM

Post #2 of 7 (5724 views)

Permalink

----- Original Message ----
> From: "guy@mobi1e.me" <guy@mobi1e.me>
> To: secureshell@securityfocus.com
> Sent: Sat, January 15, 2011 9:19:15 PM
> Subject: simulate connection with netcat
>
> Hello,
>
> my long-term intention is to write a cross-platform GUI-authpf-client
> without using libssh or libssh2. Before I get into that I'd like to simulate
> the ssh-connection/authentication via netcat.
> I took a look at the RFCs but don't get it working.
>
> % nc 127.0.0.1 22
> SSH-2.0-OpenSSH_5.2
> SSH-2.0-OpenSSH_5.2 <-- entered by me
> ... a lot of text ...
>
> What do I enter now to authenticate?
> My attempts resulted in "Packet corrupt".

SSH uses a binary protocol. Getting authenticated is far more complex than
writting something at your keyboard by hand.

You can find pointers to the related RFCs here:
http://en.wikipedia.org/wiki/Secure_Shell

- Salva

Re: simulate connection with netcat [ In reply to ]

niklas at brueckenschlaeger

Jan 17, 2011, 10:08 AM

Post #3 of 7 (5719 views)

Permalink

Why don't you want to use libssh? Maintaining a custom implementation of
SSh adds lots of complexity to your plain GUI task.

-- niklas

On Mon, 2011-01-17 at 09:43 -0800, Salvador Fandino wrote:
>
>
>
> ----- Original Message ----
> > From: "guy@mobi1e.me" <guy@mobi1e.me>
> > To: secureshell@securityfocus.com
> > Sent: Sat, January 15, 2011 9:19:15 PM
> > Subject: simulate connection with netcat
> >
> > Hello,
> >
> > my long-term intention is to write a cross-platform GUI-authpf-client
> > without using libssh or libssh2. Before I get into that I'd like to simulate
> > the ssh-connection/authentication via netcat.
> > I took a look at the RFCs but don't get it working.
> >
> > % nc 127.0.0.1 22
> > SSH-2.0-OpenSSH_5.2
> > SSH-2.0-OpenSSH_5.2 <-- entered by me
> > ... a lot of text ...
> >
> > What do I enter now to authenticate?
> > My attempts resulted in "Packet corrupt".
>
> SSH uses a binary protocol. Getting authenticated is far more complex than
> writting something at your keyboard by hand.
>
> You can find pointers to the related RFCs here:
> http://en.wikipedia.org/wiki/Secure_Shell
>
> - Salva

Re: simulate connection with netcat [ In reply to ]

martins.felipe.security at gmail

Jan 17, 2011, 11:39 AM

Post #4 of 7 (5703 views)

Permalink

When you try to connect to a SSH Server it exchanges a session key, you
would have to give that to the server before authentication.
Like Salva said, it's far more complicated than that.

Best Regards

---
Felipe Martins
Security Analyst

Skype: martins.felipe
URL: http://www.felipemartins.info/
E-mail: martins.felipe.security@gmail.com

On 17/01/2011 15:43, Salvador Fandino wrote:
>
>
>
> ----- Original Message ----
>> From: "guy@mobi1e.me"<guy@mobi1e.me>
>> To: secureshell@securityfocus.com
>> Sent: Sat, January 15, 2011 9:19:15 PM
>> Subject: simulate connection with netcat
>>
>> Hello,
>>
>> my long-term intention is to write a cross-platform GUI-authpf-client
>> without using libssh or libssh2. Before I get into that I'd like to simulate
>> the ssh-connection/authentication via netcat.
>> I took a look at the RFCs but don't get it working.
>>
>> % nc 127.0.0.1 22
>> SSH-2.0-OpenSSH_5.2
>> SSH-2.0-OpenSSH_5.2<-- entered by me
>> ... a lot of text ...
>>
>> What do I enter now to authenticate?
>> My attempts resulted in "Packet corrupt".
> SSH uses a binary protocol. Getting authenticated is far more complex than
> writting something at your keyboard by hand.
>
> You can find pointers to the related RFCs here:
> http://en.wikipedia.org/wiki/Secure_Shell
>
> - Salva

Re: simulate connection with netcat [ In reply to ]

guy at mobi1e

Jan 19, 2011, 9:49 AM

Post #5 of 7 (5734 views)

Permalink

Thanks for all advises.
I actually don't need a full ssh implementation. The thing a wanted was a simple password-authentification for non-technical users without support for rsa-keys, remote execution etc.
But it sounds to complicated for a side-project...

Problem solved. Not quite the solution I hoped for but anyway...

regards,
jake

On Jan 17, 2011, at 8:39 PM, Felipe Martins wrote:

> When you try to connect to a SSH Server it exchanges a session key, you would have to give that to the server before authentication.
> Like Salva said, it's far more complicated than that.
>
> Best Regards
>
> ---
> Felipe Martins
> Security Analyst
>
> Skype: martins.felipe
> URL: http://www.felipemartins.info/
> E-mail: martins.felipe.security@gmail.com
>
>
> On 17/01/2011 15:43, Salvador Fandino wrote:
>>
>>
>>
>> ----- Original Message ----
>>> From: "guy@mobi1e.me"<guy@mobi1e.me>
>>> To: secureshell@securityfocus.com
>>> Sent: Sat, January 15, 2011 9:19:15 PM
>>> Subject: simulate connection with netcat
>>>
>>> Hello,
>>>
>>> my long-term intention is to write a cross-platform GUI-authpf-client
>>> without using libssh or libssh2. Before I get into that I'd like to simulate
>>> the ssh-connection/authentication via netcat.
>>> I took a look at the RFCs but don't get it working.
>>>
>>> % nc 127.0.0.1 22
>>> SSH-2.0-OpenSSH_5.2
>>> SSH-2.0-OpenSSH_5.2<-- entered by me
>>> ... a lot of text ...
>>>
>>> What do I enter now to authenticate?
>>> My attempts resulted in "Packet corrupt".
>> SSH uses a binary protocol. Getting authenticated is far more complex than
>> writting something at your keyboard by hand.
>>
>> You can find pointers to the related RFCs here:
>> http://en.wikipedia.org/wiki/Secure_Shell
>>
>> - Salva
>

Re: simulate connection with netcat [ In reply to ]

martins.felipe.security at gmail

Jan 22, 2011, 9:18 AM

Post #6 of 7 (5680 views)

Permalink

Jake,

For non technical users you can use ssh as a CA, you can create to
each user a public key inside a USB Pendrive and them configure their
ssh clients (like a portable putty, and so) with that certificate (key).
This way they can authenticate to your server.

---
Felipe Martins
Security Analyst

Skype: martins.felipe
URL: http://www.felipemartins.info/
E-mail: martins.felipe.security@gmail.com

On 19/01/2011 15:49, guy@mobi1e.me wrote:
> Thanks for all advises.
> I actually don't need a full ssh implementation. The thing a wanted was a simple password-authentification for non-technical users without support for rsa-keys, remote execution etc.
> But it sounds to complicated for a side-project...
>
> Problem solved. Not quite the solution I hoped for but anyway...
>
> regards,
> jake
>
>
> On Jan 17, 2011, at 8:39 PM, Felipe Martins wrote:
>
>> When you try to connect to a SSH Server it exchanges a session key, you would have to give that to the server before authentication.
>> Like Salva said, it's far more complicated than that.
>>
>> Best Regards
>>
>> ---
>> Felipe Martins
>> Security Analyst
>>
>> Skype: martins.felipe
>> URL: http://www.felipemartins.info/
>> E-mail: martins.felipe.security@gmail.com
>>
>>
>> On 17/01/2011 15:43, Salvador Fandino wrote:
>>>
>>>
>>> ----- Original Message ----
>>>> From: "guy@mobi1e.me"<guy@mobi1e.me>
>>>> To: secureshell@securityfocus.com
>>>> Sent: Sat, January 15, 2011 9:19:15 PM
>>>> Subject: simulate connection with netcat
>>>>
>>>> Hello,
>>>>
>>>> my long-term intention is to write a cross-platform GUI-authpf-client
>>>> without using libssh or libssh2. Before I get into that I'd like to simulate
>>>> the ssh-connection/authentication via netcat.
>>>> I took a look at the RFCs but don't get it working.
>>>>
>>>> % nc 127.0.0.1 22
>>>> SSH-2.0-OpenSSH_5.2
>>>> SSH-2.0-OpenSSH_5.2<-- entered by me
>>>> ... a lot of text ...
>>>>
>>>> What do I enter now to authenticate?
>>>> My attempts resulted in "Packet corrupt".
>>> SSH uses a binary protocol. Getting authenticated is far more complex than
>>> writting something at your keyboard by hand.
>>>
>>> You can find pointers to the related RFCs here:
>>> http://en.wikipedia.org/wiki/Secure_Shell
>>>
>>> - Salva

Re: simulate connection with netcat [ In reply to ]

guy at mobi1e

Jan 24, 2011, 9:54 AM

Post #7 of 7 (5692 views)

Permalink

That's an interesting idea, thx.
I'll forward the suggestion to the other admin.

jake

On Jan 22, 2011, at 6:18 PM, Felipe Martins wrote:

> Jake,
>
> For non technical users you can use ssh as a CA, you can create to each user a public key inside a USB Pendrive and them configure their ssh clients (like a portable putty, and so) with that certificate (key). This way they can authenticate to your server.
>
> ---
> Felipe Martins
> Security Analyst
>
> Skype: martins.felipe
> URL: http://www.felipemartins.info/
> E-mail: martins.felipe.security@gmail.com
>
>
> On 19/01/2011 15:49, guy@mobi1e.me wrote:
>> Thanks for all advises.
>> I actually don't need a full ssh implementation. The thing a wanted was a simple password-authentification for non-technical users without support for rsa-keys, remote execution etc.
>> But it sounds to complicated for a side-project...
>>
>> Problem solved. Not quite the solution I hoped for but anyway...
>>
>> regards,
>> jake
>>
>>
>> On Jan 17, 2011, at 8:39 PM, Felipe Martins wrote:
>>
>>> When you try to connect to a SSH Server it exchanges a session key, you would have to give that to the server before authentication.
>>> Like Salva said, it's far more complicated than that.
>>>
>>> Best Regards
>>>
>>> ---
>>> Felipe Martins
>>> Security Analyst
>>>
>>> Skype: martins.felipe
>>> URL: http://www.felipemartins.info/
>>> E-mail: martins.felipe.security@gmail.com
>>>
>>>
>>> On 17/01/2011 15:43, Salvador Fandino wrote:
>>>>
>>>>
>>>> ----- Original Message ----
>>>>> From: "guy@mobi1e.me"<guy@mobi1e.me>
>>>>> To: secureshell@securityfocus.com
>>>>> Sent: Sat, January 15, 2011 9:19:15 PM
>>>>> Subject: simulate connection with netcat
>>>>>
>>>>> Hello,
>>>>>
>>>>> my long-term intention is to write a cross-platform GUI-authpf-client
>>>>> without using libssh or libssh2. Before I get into that I'd like to simulate
>>>>> the ssh-connection/authentication via netcat.
>>>>> I took a look at the RFCs but don't get it working.
>>>>>
>>>>> % nc 127.0.0.1 22
>>>>> SSH-2.0-OpenSSH_5.2
>>>>> SSH-2.0-OpenSSH_5.2<-- entered by me
>>>>> ... a lot of text ...
>>>>>
>>>>> What do I enter now to authenticate?
>>>>> My attempts resulted in "Packet corrupt".
>>>> SSH uses a binary protocol. Getting authenticated is far more complex than
>>>> writting something at your keyboard by hand.
>>>>
>>>> You can find pointers to the related RFCs here:
>>>> http://en.wikipedia.org/wiki/Secure_Shell
>>>>
>>>> - Salva
>

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