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

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Archive for the ‘https’ Category

Hardening: sshd_config – How to configure the OpenSSH server | SSH.COM

Posted by jpluimers on 2020/06/05

If you want to harden your ssh server, read at least [WayBack] sshd_config – How to configure the OpenSSH server | SSH.COM.

After that use some ssh tools to check your config from the outside world. They work in a similar way as the TLS/SSL/https scans from Source: SSL Server Test (Powered by Qualys SSL Labs) or these console based scans and documentation references:

Simiarly for SSH:

Then read further on more in depth SSH topics around key management:

–jeroen

 

Posted in Encryption, Hashing, https, HTTPS/TLS security, OpenSSL, Power User, Security, testssl.sh | Leave a Comment »

SSH through HTTPS

Posted by jpluimers on 2020/05/04

Often, hotspots only allow http/https traffic. Other traffic – like SSH – is blocked. Nowadays, fewer hotspots block that, but too many still do.

So it can be worth a while to route your SSH server through HTTPS (I don’t like Web-based SSH that much as terminal emulation in browsers isn’t that well yet, but that seems to change rapidly, more on that in the “Further reading” section below).

After some background reading at apache – Tunnel over HTTPS – Stack Overflow, here are a few links that help you do it:

Server side: DAG: Tunneling SSH over HTTP(S).

You need:

  • An internet connected Apache server (eg. with IP address 10.1.2.3)
  • A FQDN that points to this IP address (eg. ssh.yourdomain.com)
  • A virtual host configuration in Apache for this domain (eg. /etc/httpd/conf.d/ssh.yourdomain.com.conf)
  • A configuration to adapt ssh to use the HTTP tunnel

Read more at DAG: Tunneling SSH over HTTP(S) and SSH over SSL, a quick and minimal config..

Client side: Using SSH over the HTTPS port · GitHub Help.

Steps:

  1. Test of it works at all
  2. Edit your local ~/.ssh/config file to redirect SSH to HTTPS

Read more at Using SSH over the HTTPS port · GitHub Help.

Using Putty and an HTTP proxy to ssh anywhere through firewalls | Me in IT.

the Digital me: SSH Tunneling Proxy using Putty on Windows and Linux (Unblock YouTube / Orkut / Facebook).

Tunneling SSH through HTTP proxies using HTTP Connect – ArchWiki.

HTTP Tunneling – ArchWiki.

Running SSHD on port 443.

Not all proxy configurations and hotspots support this. But it might be worth a look: SSH Over Proxy.

Further reading: Web-based SSH.

SSH plugins for browsers:

Web based SSH:

–jeroen

Posted in Communications Development, Development, Encryption, HTTP, https, HTTPS/TLS security, Internet protocol suite, Power User, Security, SSH, TCP | Leave a Comment »

if you allow users to register email addresses on your domain, make sure they can’t get: admin@ administrator@ hostmaster@…

Posted by jpluimers on 2019/12/16

Great tip from: [Archive.isMichal Špaček on Twitter: “Friendly reminder: if you allow users to register email addresses on your domain, make sure they can’t get: admin@ administrator@ hostmaste… https://t.co/wUHXrQC2J0”:

 Friendly reminder: if you allow users to register email addresses on your domain, make sure they can’t get:
  • admin@
  • administrator@
  • hostmaster@
  • postmaster@
  • webmaster@ (and others from RFC 2142)

otherwise users might be able to get an HTTPS certificate for your domain.

–jeroen

Read the rest of this entry »

Posted in Encryption, https, Let's Encrypt (letsencrypt/certbot), Power User, Security | Leave a Comment »

Tools for TCP tunnels over HTTP/HTTPS

Posted by jpluimers on 2019/01/16

With the advent of WebSockets, it looks like TCP tunnels over HTTP/HTTPS are gaining more ground and I need to put some research time in them.

Some old to new links:

CONNECT requests are not supported by many HTTP proxies, especially in larger organisations, so chisel and crowbar have a much bigger chance there.

And of course there is SoftEtherVPN/SoftEtherVPN: A Free Cross-platform Multi-protocol VPN Software. * For support, troubleshooting and feature requests we have http://www.vpnusers.com/. For critical vulnerability please email us. (mail address is on the header.).

However, that is a VPN solution which is much broader than just a single TCP tunnel. You can so similar things with OpenVPN, but over HTTP/HTTPS, also requires CONNECT:

SoftEtherVPN seems to be more versatile though. I blogged about that before, but back then didn’t have needs for it yet. VPN over HTTPS: Ultimate Powerful VPN Connectivity – SoftEther VPN Project.

–jeroen

via: [WayBackVPN through only http – Server Fault answer by [WayBack] neutrinus

Posted in Communications Development, Development, HTTP, https, Internet protocol suite, Network-and-equipment, OpenVPN, Power User, TCP, VPN, WebSockets, Windows-Http-Proxy | Leave a Comment »

Use TLS 1.2 or higher, as TLS 1.1 is phased out on many sites, after TLS 1.0/SLL has been disabled by most for a while now

Posted by jpluimers on 2018/07/23

If you get an error like this in one of your tools

OpenSSL: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version

it means you are using a tool not yet properly supporting TLS 1.2 or higher.

Or in other words: update your tool set.

The reason is that – after turning off TLS 1.0 a while ago – more and more sites do the same for TLS 1.1.

A prime example of a site that warned on this in a clear way very early on is github:

Others have done this too, for instance:

TLS 1.0 is vulnerable to many attacks, and certain configurations of TLS 1.1 as well (see for instance [WayBack] What are the main vulnerabilities of TLS v1.1? – Information Security Stack Exchange), which means that properly configuring the non-vulnerable TLS 1.1 over times gets more and more complex. An important reason to say goodbye to that as well, as TLS 1.2 (from 2008) is readily available for a long time. The much more recent TLS 1.3 (from 2018) will take a while to proliferate.

I ran in the above error because on one of my systems, an old version of wget was luring around, so I dug up the easiest place to download recent Windows binaries for both win32 (x86) and win64 (x86_64):

[WayBack] eternallybored.org: GNU Wget for Windows having a table indicating the OpenSSL version for each wget build.

–jeroen

Reference: Transport Layer Security – Wikipedia: History and development

Posted in *nix, https, HTTPS/TLS security, OpenSSL, Power User, Security, wget | Leave a Comment »

Packet Sender is a good tool when debugging protocols: free utility to send & receive network packets. TCP, UDP, SSL

Posted by jpluimers on 2018/03/07

It was fitting to bump into [WayBack] Packet Sender is a good tool when debugging protocols…” Written by Dan Nagle… – Lars Fosdal – Google+ on the day presenting [WayBack] Conferences/Network-Protocol-Security.rst at master · jpluimers/Conferences · GitHub

It also means that libssh2-delphi is getting a bit more love soon and will move to github as well after a conversion from mercurial.

Some of the things I learned or got confirmed teaching the session (I love learning by teaching):

Here is some more info:

–jeroen

Read the rest of this entry »

Posted in Communications Development, Delphi, Development, Encryption, Hardware, Harman Kardon, Home Audio/Video, HTTP, https, HTTPS/TLS security, Internet protocol suite, Let's Encrypt (letsencrypt/certbot), OpenSSL, Power User, Security, Software Development, TCP, TLS | 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 »

ssl/ssh multiplexer

Posted by jpluimers on 2017/08/07

sslh accepts connections on specified ports, and forwards them further based on tests performed on the first data packet sent by the remote client.

Probes for HTTP, SSL, SSH, OpenVPN, tinc, XMPP are implemented, and any other protocol that can be tested using a regular expression, can be recognised. A typical use case is to allow serving several services on port 443 (e.g. to connect to ssh from inside a corporate firewall, which almost never block port 443) while still serving HTTPS on that port.

Hence sslh acts as a protocol demultiplexer, or a switchboard. Its name comes from its original function to serve SSH and HTTPS on the same port.

sslh supports IPv6, privilege dropping, transparent proxying, and more.

Interesting…

–jeroen

Posted in *nix, https, Linux, OpenSSL, OpenVPN, Power User, Security | Leave a Comment »

Sending various HTTP request kinds using curl

Posted by jpluimers on 2017/07/25

I’ve been using cURL but always had a feeling not to its potential basically because the cURL man page [WayBack] is both massive and lacks concrete useful practical examples.

For instance, I knew about the --header and --verbose options (I always use verbose names even though shorter -H and -v exist) to pass a specific header and get verbose output, but the man page basic examples like this by Tader:

curl --header --verbose "X-MyHeader: 123" www.google.com

source: How to send a header using a HTTP request through a curl call? – Stack Overflow [WayBack]

There are some more examples at bropages.org/curl but they’re hardly organised or documented.

So I was really glad I found the below answer [WayBack] by Amith Koujalgi to web services – HTTP POST and GET using cURL in Linux – Stack Overflow.

But first note that recent versions (around 7.22 or higher) of cURL now need to combine the --silent and --show-error (or in short -sS) parameters to suppress progress but show errors: linux – How do I get cURL to not show the progress bar? – Stack Overflow [WayBack]

Back to the examples

Read the rest of this entry »

Posted in *nix, Communications Development, cURL, Delphi, Development, HTTP, https, Internet protocol suite, JavaScript/ECMAScript, JSON, Power User, REST, Scripting, Security, Software Development, TCP, TLS, XML, XML/XSD | 1 Comment »