Hardening Your Web Servers SSL Ciphers Hynek Schlawack. There are many wordy articles on configuring your web servers TLS ciphers. This is not one of them. Instead I will share a configuration which is both compatible enough for todays needs and scores a straight A on Qualyss SSL Server Test. Disclaimer Im updating this post continually in order to represent what I consider the best practice in the moment there are way too many dangerously outdated articles about TLS deployment out there already. Therefore it may be a good idea to check back from time to time because the crypto landscape is changing pretty quickly at the moment. You can follow me on Twitter to get notified about noteworthy changes. Windows Server 2008 includes Internet Information Services IIS 7. 0. This new version makes several big changes in the way that SSL certificates are generated. HTTPS also called HTTP over Transport Layer Security TLS, HTTP over SSL, and HTTP Secure is a communications protocol for secure communication over a computer. June 28, 2011. I write this post after a hellish experience that lasted a couple of hours trying to sort out the SSL certificate for SSRS. Basically the story goes. Apache web server is a very popular web server to host website on the web. In this tutorial, Ill cover some main tips to secure your Apache web server. If you find any factual problems, please reach out to me and I will fix it ASAP. Rationale. If you configure a web servers TLS configuration, you have primarily to take care of three things disable SSL 2. FUBAR and SSL 3. POODLE,disable TLS 1. CRIME,disable weak ciphers DES3. HowTo Install Redmine in a subURI on Windows with Apache HowTo Install Redmine in a subURI on Windows with Apache. Install Apache HTTP server 2. 2. x. Instructions for Apache SSL Certificate Installation Apache OpenSSL and ModSSL web server configurations. DES, RC4, prefer modern ciphers AES, modes GCM, and protocols TLS 1. You should also put effort into mitigating BREACH. Thats out of scope here though as its largely application dependent. Software and Versions. On the server side you should update your Open. SSL to 1. 0. 1c so you can support TLS 1. GCM, and ECDHE as soon as possible. Fortunately thats already the case in Ubuntu 1. On the client side the browser vendors are starting to catch up. As of now, Chrome 3. Internet Explorer 1. Windows 8, Safari 7 on OS X 1. Firefox 2. 6 all support TLS 1. RC4. There used to be a bullet point suggesting to use RC4 to avoid BEAST and Lucky Thirteen. And ironically that used to be the original reason for this article when Lucky Thirteen came out the word in the streets was use RC4 to mitigate and everyone was like how. Unfortunately shortly thereafter RC4 was found broken in a way that makes deploying TLS with it nowadays a risk. How to Install and Configure Php 5. 2. 5 and Apache 2. 2. 8 in Windows Vista. Many web developers want to run Apache and PHP on their own computer. This article gives a. History. 28. 08. 2017 Released v1. 8. Windows 2016 powershell version 5. 1. 14393. 1532 and maybe others require else and elseif statements in the same line after to. DigiCert Setting up SSL Certificates on all major server types. SSL setup guide tutorials. A practical guide to secure and harden Apache Web Server. 1. Introduction The Web Server is a crucial part of webbased applications. Apache Web Server is often. While BEAST et al require an active attack on the browser of the victim, passive attacks on RC4 ciphertext are getting stronger every day. In other words its possible that it will become feasible to decrypt intercepted RC4 traffic eventually and the NSA probably already is. Microsoft even issued a security advisory that recommends to disable RC4. As of 2. 01. 5, theres even an RFC. The String. ECDHAESGCM DHAESGCM ECDHAES2. DHAES2. 56 ECDHAES1. DHAES RSAAESGCM RSAAES NULL MD5 DSS. You can test it against your Open. SSL installation usingopenssl ciphers v ECDHAESGCM DHAESGCM ECDHAES2. DHAES2. 56 ECDHAES1. DHAES RSAAESGCM RSAAES NULL MD5 DSS. Youll get Best possible encryption in all browsers. Perfect forward secrecy if your web server, your Open. SSL, and their browser support it. It doesnt offer RC4 even as a fallback. Although its inclusion at the end of the cipher string shouldnt matter, active downgrade attacks on SSLTLS exist and having RC4 as part of the the cipher string you potentially expose all of your users to it. Same goes for 3. DES as of SWEET3. Using ECDSA for authentication is even as of 2. Hence its completely ignored by the string. That makes it being sorted after RSA which is probably not what you want if you went the lengths to obtain an EC certificate. However if you manage to deploy a dual certificate setup which you still need nowadays, you probably dont need this article and it would have made the string twice as long. The string also prefers AES 2. AES 1. 28 except for GCM which is preferred over everything else. It does so mostly for liability reasons because customers may insist on it for bogus reasons. However quoth a cryptographer AES 1. AES anythingelse, at least not in ways you care about. The very simplified gist here is that the only reason for having 2. AES 2. 56. But let me stress that both are fine. Its just that adding AES 2. So if AES 1. 28 is fine for you, feel free to add an AES2. 56 to the end of the cipher string like I do. Apache. SSLProtocol ALL SSLv. SSLv. 3. SSLHonor. Cipher. Order On. SSLCipher. Suite ECDHAESGCM DHAESGCM ECDHAES2. DHAES2. 56 ECDHAES1. DHAES RSAAESGCM RSAAES NULL MD5 DSS. This works on both Apache 2. If your Open. SSL doesnt support the preferred modern ciphers like the still common 0. Please note you need Apache 2. ECDHE and ECDSA. You can circumvent that limitation by putting an SSL proxy like hitch or even nginx in front of it and let Apache serve only plain HTTP. TLS compression is a bit more complicated as of Apache 2. Apache. For Apache 2. SSLCompression Off. Currently the default is On. But that changed from 2. The good news for Ubuntu admins is that Ubuntu has back ported that option into their 2. On RHELCent. OS you used to have to set an environment variable but that has been fixed too and should be correct by default now. On. sslprotocols TLSv. TLSv. 1. 1 TLSv. 1. ECDHAESGCM DHAESGCM ECDHAES2. DHAES2. 56 ECDHAES1. DHAES RSAAESGCM RSAAES NULL MD5 DSS. TLS compression depends on the version of nginx and the version of Open. SSL. If Open. SSL 1. If an older Open. SSL is installed, youll need at least nginx 1. Have a look at this serverfault answer for more details. TL DR on TLS compression nginx if youre using Ubuntu 1. Open. SSL 1. 0. 1nginx 1. Cent. OSRed Hat Enterprise Linux 6. Although Cent. OS 6. Open. SSL that is capable of ECDHE key exchange, it doesnt ship an nginx and the nginx you get from nginx. Open. SSL. Therefore openssl ciphers will confusingly show you all the shiny ciphers but nginx just wont offer it to the clients. Thats terrible because it costs you PFS for IE browsers. Youll have to compile nginx yourself or source it from an alternative package index EPEL for instance. HAProxy. For TLS matters HAProxy shouldnt be older than version 1. ECDHAESGCM DHAESGCM ECDHAES2. DHAES2. 56 ECDHAES1. DHAES RSAAESGCM RSAAES NULL MD5 DSS. ECDHAESGCM DHAESGCM ECDHAES2. DHAES2. 56 ECDHAES1. DHAES RSAAESGCM RSAAES NULL MD5 DSS. Bonus Points. Qualys updated their requirements on 2. Amaterial. If you want an A though, youll need to tweak your HTTP headers too. This goes way beyond the scope of this article, check out securityheaders. Finally. Make sure to test your server afterwards If you want to learn more about deploying SSLTLS, Qualyss SSLTLS Deployment Best Practices are a decent primer. Since I wrote this article in 2. TLS checkers appeared. Mozilla even built an observatory that aggregates their results. However their results vary and sometimes even contradict each other so I recommend to focus on one. In my case its the Qualys for TLS and securityheaders. For investigating the SSLTLS behavior of your browser, Qualys also has a page for that. History. Since Im keeping this up to date, Im going to document changes for returning visitors 2. Added DHE param size to HAProxy. Removed 3. DES because of SWEET3. This drops IE 8 on Windows XP support which shouldnt be a concern in 2. The new weakdhLogjam attack doesnt affect you if you followed these instructions. It might be worthwhile though to create your own DH groups with at least 2. Added a note on ECDSA because there seemed to be some confusion about it. Added HAProxy, courtesy of Sander Klein. Updated the TLS compression part about Red HatCent. OS. TL DR its secure by default now. Clarified that Internet Explorer 8 on Windows XP works fine with TLSv.
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