The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Internet protocol suite’ Category

Using hardware security tokens cross-platform is only slightly more complicat…

Posted by jpluimers on 2018/01/17

Thanks for the excellent comment explaining how to use hardware tokens as a comment to [WayBack] Using hardware security tokens cross-platform is only slightly more complicated than piloting a Space Shuttle. ##sarcasm – Jan Wildeboer – Google+

Jan Wildeboer:

+Jeroen Wiert Pluimers OK. Let’s look a bit at how this works. There are several competing standards/ways to use a security token. Typically you’ll decide between the two most used ones. As a CCID device AKA SmartCard with OpenSC or using gpg-agent. And that’s an either/or question. Some of the security tokens can only work with gpg-agent, some can do both (but not at the same time) and some are only useful as CCID style (e.g. the Nitrokey HSM).

OK. So now we look at platforms. CCID using OpenSC mostly works everywhere, but you might need to install some additional software depending on your OS. Older versions of MacOS X were notoriously bad, since (High) Sierra it has become better.

On Linux it again really depends. The gnome-keyring-agent that is active in a Gnome session really messes everything up, so better deactivate that. Which is not really trivial. But you have to have a socket for ssh-agent to pick up the key, so some stuff goes to your .bash.rc and you have to make some changes to Gnome config.

If you want to use a Yubikey for 2FA, note that it cannot do TOTP (Time based One Time Password) which Amazon wants for AWS auth. So you need another helper app on your computer.

Here’s some articles that explain it in detail:

The middle two links are actually part of the series [WayBack] Yubikey All The Things | EngineerBetter | More than Cloud Foundry specialists which has a third post [WayBack] Yubikeys for Static Secrets | EngineerBetter | More than Cloud Foundry specialists

–jeroen

Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, Power User, Security, SSH, TCP | Leave a Comment »

badssl.com

Posted by jpluimers on 2018/01/11

I wish I had bumped into this when it got released in 2015: [WayBackbadssl.com hosted in the cloud and maintained by two people from Google and Mozilla.

Where ssllabs.com is for checking server-side certificates, this one is for checking clients against many, many (did I already write MANY?) server side configurations both good (with a varying set of security settings like cyphers and key exchanges) and bad.

One of the bad ones is expired.badssl.com which your clients should not be able to connect to without throwing a big error.

Sources are at [WayBack] GitHub – chromium/badssl.com: Memorable site for testing clients against bad SSL configs.

Before using, please read their

Disclaimer

badssl.com is meant for manual testing of security UI in web clients.

Most subdomains are likely to have stable functionality, but anything could change without notice. If you would like a documented guarantee for a particular use case, please file an issue. (Alternatively, you could make a fork and host your own copy.)

badssl.com is not an official Google product. It is offered “AS-IS” and without any warranties.

–jeroen

Posted in Communications Development, Development, HTTP, https, Internet protocol suite, Security, Software Development, TCP, TLS, Web Development | Leave a Comment »

Helft homepaginas van Nederlandse overheidswebsites gebruikt geen https – IT Pro – Nieuws – Tweakers

Posted by jpluimers on 2017/12/15

Still some work to do for some of my sites:

–jeroen

[WayBackHelft homepaginas van Nederlandse overheidswebsites gebruikt geen https – IT Pro – Nieuws – Tweakers

Posted in Communications Development, Development, Encryption, https, Internet protocol suite, Power User, Security, TLS | Leave a Comment »

Some notes on having static-web site owners upload their content over SFTP

Posted by jpluimers on 2017/12/14

Yes, there are still static web-sites. A long time ago, they were uploaded over FTP. Now many use more secure protocols.

So here are some links and notes to allow this on a Linux based host running OpenSSH.

I got to the above via these two links:

An alternative might be web-dave, but that would probably mean some hassle to separate uploading the site from accessing the site.

[Archive.isHow To Set Up WebDAV With Apache2 On OpenSUSE 12.2

–jeroen

Posted in *nix, Communications Development, Development, Internet protocol suite, Linux, openSuSE, Power User, SSH, SuSE Linux, TCP | Leave a Comment »

XS4ALL has stopped providing ftp in the middle of 2017: now you can use sftp or sftp.

Posted by jpluimers on 2017/12/03

As of 20170711, the servername ftp.xs4all.nl does not support the ftp protocol any more; xs4all clients can only use the server sftp.xs4all.nl on port 22.

I missed that because I hardly use ftp except for the few rare occasions where I was in an environment without ftp.

So recently I found out: good move!

Since I still need this every now and then (but far less often than 10 years ago), I have set up a very small ftp server at home with limited storage and very limited users that I can turn on/off when needed.

Much better solution.

–jeroen

Source: [WayBackXS4ALL gaat stoppen met ondersteuning van ftp – Security.NL

Posted in Communications Development, Development, FTP, Internet protocol suite, Power User, TCP | Leave a Comment »

immediate “Too many authentication failures” – check your authentication methods

Posted by jpluimers on 2017/11/15

If you ever ssh into something and immediately get the immediate Too many authentication failures message, then you’ve probably mixed your authentication methods.

Follow the steps in [WayBackssh – Too many authentication failures for username – Super User (thanks [WayBackJohn T and [WayBackBen West).

First check out whats wrong by slowly increasing the number of -v parameters to make output more verbose:

ssh -v
ssh -v -v
ssh -v -v -v

Then try to find out which authentication method fails: usually it’s a private key that’s wrong.

I’ve had success in various cases where I screwed up with these ssh parameters:

-o PubkeyAuthentication=no
-i some_id_rsa -o IdentitiesOnly=yes

–jeroen

 

Posted in *nix, Communications Development, Development, Internet protocol suite, Power User, Software Development, SSH, TCP | Leave a Comment »

TLS tests for your mail server

Posted by jpluimers on 2017/11/09

Need to do some more research on this to ensure I didn’t goof up:

–jeroen

Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, postfix, Power User, Security, sendmail, SMTP | Leave a Comment »

(52) You Give REST a Bad Name – YouTube

Posted by jpluimers on 2017/11/02

(Usually the “state transfer” in Representational state transfer fails)

Video via +Kristian Köhntopp “Die 90er haben angerufen und wollen ihre Amiga Videos und ihre Corba Specs zurück haben.” (the 90s called wanting their Amiga Videos and Corba Specs back)

[WayBack] https://plus.google.com/+KristianK%C3%B6hntopp/posts/58D9BisX5Dj

–jeroen

Posted in Communications Development, Development, Fun, HTTP, Internet protocol suite, REST, TCP | Leave a Comment »

IANA Service Name and Transport Protocol Port Number Registry

Posted by jpluimers on 2017/09/28

Cool! Search by port number, name, user or description straight from the source: IANA.org Service Name and Transport Protocol Port Number Registry

Posted in Communications Development, Development, Internet protocol suite, Network-and-equipment, Power User, TCP | Leave a Comment »

Don’t Use Regular Expressions To Parse IP Addresses!

Posted by jpluimers on 2017/09/21

Interesting piece: Don’t Use Regular Expressions To Parse IP Addresses! [WayBack]

TL;DR:

When have neither then for quad-dotted decimal IPv4 addresses (ignoring for instance octals and grouped quads), this is suitable: regex – Regular expression to match DNS hostname or IP Address? – Stack Overflow [WayBack]

ValidIpAddressRegex = "^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$";

Which explained looks like this:

https://regex101.com/r/Wyr2Zd/1

Regular expression:

/ ^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$ / g

Explanation:

  • ^ asserts position at start of the string
    • 1st Capturing Group (([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}
      • {3} Quantifier — Matches exactly 3 times
        A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you’re not interested in the data

        • 2nd Capturing Group ([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
          • 1st Alternative [0-9]
            • Match a single character present in the list below [0-9]
              0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
          • 2nd Alternative [1-9][0-9]
            • Match a single character present in the list below [1-9]
              1-9 a single character in the range between 1 (ASCII 49) and 9 (ASCII 57) (case sensitive)
            • Match a single character present in the list below [0-9]
              0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
          • 3rd Alternative 1[0-9]{2}
            • 1 matches the character 1 literally (case sensitive)
            • Match a single character present in the list below [0-9]{2}
              {2} Quantifier — Matches exactly 2 times
              0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
          • 4th Alternative 2[0-4][0-9]
            • 2 matches the character 2 literally (case sensitive)
            • Match a single character present in the list below [0-4]
              0-4 a single character in the range between 0 (ASCII 48) and 4 (ASCII 52) (case sensitive)
            • Match a single character present in the list below [0-9]
              0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
          • 5th Alternative 25[0-5]
            • 25 matches the characters 25 literally (case sensitive)
            • Match a single character present in the list below [0-5]
              0-5 a single character in the range between 0 (ASCII 48) and 5 (ASCII 53) (case sensitive)
        • \. matches the character . literally (case sensitive)
    • 3rd Capturing Group ([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
      • 1st Alternative [0-9]
        • Match a single character present in the list below [0-9]
          0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
      • 2nd Alternative [1-9][0-9]
        • Match a single character present in the list below [1-9]
          1-9 a single character in the range between 1 (ASCII 49) and 9 (ASCII 57) (case sensitive)
        • Match a single character present in the list below [0-9]
          0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
      • 3rd Alternative 1[0-9]{2}
        • 1 matches the character 1 literally (case sensitive)
        • Match a single character present in the list below [0-9]{2}
          {2} Quantifier — Matches exactly 2 times
          0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
      • 4th Alternative 2[0-4][0-9]
        • 2 matches the character 2 literally (case sensitive)
        • Match a single character present in the list below [0-4]
          0-4 a single character in the range between 0 (ASCII 48) and 4 (ASCII 52) (case sensitive)
        • Match a single character present in the list below [0-9]
          0-9 a single character in the range between 0 (ASCII 48) and 9 (ASCII 57) (case sensitive)
      • 5th Alternative 25[0-5]
        • 25 matches the characters 25 literally (case sensitive)
        • Match a single character present in the list below [0-5]
          0-5 a single character in the range between 0 (ASCII 48) and 5 (ASCII 53) (case sensitive)
  • $ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)
  • Global pattern flags
    g modifier: global. All matches (don’t return after first match)

–jeroen

Posted in *nix, Communications Development, Development, Internet protocol suite, Network-and-equipment, Power User, Software Development, TCP | Leave a Comment »