1 \section{Recommendations on practical settings}
4 \subsection{Webservers}
9 \item[Tested with Version:]
11 \item[Settings:] \mbox{}
13 %-All +TLSv1.1 +TLSv1.2
14 \begin{lstlisting}[breaklines]
15 SSLProtocol All -SSLv2 -SSLv3
16 SSLHonorCipherOrder On
18 # Add six earth month HSTS header for all users...
19 Header add Strict-Transport-Security "max-age=15768000"
20 # If you want to protect all subdomains, use the following header
21 # ALL subdomains HAVE TO support https if you use this!
22 # Strict-Transport-Security: max-age=15768000 ; includeSubDomains
24 SSLCipherSuite 'EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH+CAMELLIA256:EECDH:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:!AES128:!CAMELLIA128:!ECDSA:AES256-SHA'
27 Note again, that any cipher suite starting with ECDHE can be omitted in case of doubt.
28 %% XXX NOTE TO SELF: remove from future automatically generated lists!
30 \item[Additional settings:]
32 You should redirect everything to httpS:// if possible. In Apache you can do this with the following setting inside of a VirtualHost environment:
34 \begin{lstlisting}[breaklines]
38 RewriteRule ^.*$ https://%{SERVER_NAME}%{REQUEST_URI} [L,R=permanent]
43 \item[Justification for special settings (if needed):]
48 %XXXX ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AES:RSA+3DES:!ADH:!AECDH:!MD5:!DSS
51 \subsubsection{lighttpd}
55 %% Note: need to be checked / reviewed
57 %% Complete ssl.cipher-list with same algo than Apache
58 \todo{FIXME: this string seems to be wrongly formatted}
60 \begin{lstlisting}[breaklines]
61 $SERVER["socket"] == "0.0.0.0:443" {
63 ssl.use-sslv2 = "disable"
64 ssl.use-sslv3 = "disable"
65 #ssl.use-compression obsolete >= 1.4.3.1
66 ssl.pemfile = "/etc/lighttpd/server.pem"
67 ssl.cipher-list = 'EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH+CAMELLIA256:EECDH:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:!AES128:!CAMELLIA128:!ECDSA:AES256-SHA'
68 ssl.honor-cipher-order = "enable"
69 setenv.add-response-header = ( "Strict-Transport-Security" => "max-age=31536000")
73 As for any other webserver, you should redirect automatically http traffic toward httpS:\footnote{That proposed configuration is directly coming from lighttpd documentation: \url{http://redmine.lighttpd.net/projects/1/wiki/HowToRedirectHttpToHttps}}
75 \begin{lstlisting}[breaklines]
76 $HTTP["scheme"] == "http" {
77 # capture vhost name with regex conditiona -> %0 in redirect pattern
78 # must be the most inner block to the redirect rule
79 $HTTP["host"] =~ ".*" {
80 url.redirect = (".*" => "https://%0$0")
89 \begin{lstlisting}[breaklines]
90 ssl_prefer_server_ciphers on;
91 ssl_protocols -SSLv2 -SSLv3;
92 ssl_ciphers 'EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH+CAMELLIA256:EECDH:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:!AES128:!CAMELLIA128:!ECDSA:AES256-SHA';
93 add_header Strict-Transport-Security max-age=2592000;
94 add_header X-Frame-Options DENY;
97 %% XXX FIXME: do we need to specify dhparams? Parameter: ssl_dhparam = file. See: http://wiki.nginx.org/HttpSslModule#ssl_protocols
100 If you decide to trust NIST's ECC curve recommendation, you can add the following line to nginx's configuration file to select special curves:
102 \begin{lstlisting}[breaklines]
103 ssl_ecdh_curve sect571k1;
106 You should redirect everything to httpS:// if possible. In Nginx you can do this with the following setting:
108 \begin{lstlisting}[breaklines]
109 rewrite ^(.*) https://$host$1 permanent;
112 %\subsubsection{openssl.conf settings}
114 %\subsubsection{Differences in SSL libraries: gnutls vs. openssl vs. others}
116 \subsubsection{MS IIS}
121 When trying to avoid RC4 and CBC (BEAST-Attack) and requiring perfect
122 forward secrecy, Microsoft Internet Information Server (IIS) supports
123 ECDSA, but does not support RSA for key exchange (consider ECC suite
124 B doubts\footnote{\url{http://safecurves.cr.yp.to/rigid.html}}).
126 Since \verb|ECDHE_RSA_*| is not supported, a SSL certificate based on
127 elliptic curves needs to be used.
129 The configuration of cipher suites MS IIS will use can be configured in one
130 of the following ways:
132 \item Group Policy \footnote{\url{http://msdn.microsoft.com/en-us/library/windows/desktop/bb870930(v=vs.85).aspx}}
134 \item IIS Crypto~\footnote{\url{https://www.nartac.com/Products/IISCrypto/}}
138 Table~\ref{tab:MS_IIS_Client_Support} shows the process of turning on
139 one algorithm after another and the effect on the supported Clients
140 tested using https://www.ssllabs.com.
142 \verb|SSL 3.0|, \verb|SSL 2.0| and \verb|MD5| are turned off.
143 \verb|TLS 1.0| and \verb|TLS 2.0| are turned on.
150 Cipher Suite & Client \\
152 \verb|TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256| & only IE 10,11, OpenSSL 1.0.1e \\
153 \verb|TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256| & Chrome 30, Opera 17, Safari 6+ \\
154 \verb|TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA| & FF 10-24, IE 8+, Safari 5, Java 7\\
157 \caption{Client support}
158 \label{tab:MS_IIS_Client_Support}
161 Table~\ref{tab:MS_IIS_Client_Support} shows the algoriths from
162 strongest to weakest and why they need to be added in this order. For
163 example insiting on SHA-2 algorithms (only first two lines) would
164 eliminate all versions of Firefox, so the last line is needed to
165 support this browser, but should be placed at the bottom, so capable
166 browsers will choose the stronger SHA-2 algorithms.
168 \verb|TLS_RSA_WITH_RC4_128_SHA| or equivalent should also be added if
169 MS Terminal Server Connection is used (make sure to use this only in a
170 trusted environment). This suite will not be used for SSL, since we do
174 % \verb|TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256| ... only supported by: IE 10,11, OpenSSL 1.0.1e
175 % \verb|TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256| ... Chrome 30, Opera 17, Safari 6+
176 % \verb|TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA| ... Firefox 10-24, IE 8+, Safari 5, Java 7
179 Not supported Clients:
187 \subsection{Mail Servers}
189 This section documents the most common mail (SMTP) and IMAPs/POPs servers. Another option to secure IMAPs/POPs servers is to place them behind an stunnel server.
191 \subsubsection{Dovecot}
196 % Example: http://dovecot.org/list/dovecot/2013-October/092999.html
198 \begin{lstlisting}[breaklines]
199 ssl_cipher_list = 'EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH+CAMELLIA256:EECDH:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:!AES128:!CAMELLIA128:!ECDSA:AES256-SHA'
200 ssl_prefer_server_ciphers = yes
203 Dovecot 2.1: Almost as good as dovecot 2.2. Does not support ssl\_prefer\_server\_ciphers
205 \paragraph*{Limitations}\mbox{}\\
207 Dovecot currently does not support disabling TLS compression. Furthermore, DH parameters
208 greater than 1024bit aren't possible. The most recent version 2.2.7 of Dovecot implements
209 configurable DH parameter length
210 \footnote{\url{http://hg.dovecot.org/dovecot-2.2/rev/43ab5abeb8f0}}.
212 \subsubsection{cyrus-imapd (based on 2.4.17)}
214 \paragraph*{imapd.conf}\mbox{}\\
216 To activate SSL/TLS configure your certificate with
217 \begin{lstlisting}[breaklines]
218 tls_cert_file: .../cert.pem
219 tls_key_file: .../cert.key
222 Do not forget to add necessary intermediate certificates to the .pem file.\\
224 Limiting the ciphers provided may force (especially older) clients to connect without encryption at all! Sticking to the defaults is recommended.\\
226 If you still want to force strong encryption use
227 \begin{lstlisting}[breaklines]
228 tls_cipher_list: <...recommended ciphersuite...>
231 cyrus-imapd loads hardcoded 1024 bit DH parameters using get\_rfc2409\_prime\_1024() by default. If you want to load your own DH parameters add them PEM encoded to the certificate file given in tls\_cert\_file. Do not forget to re-add them after updating your certificate.
233 \paragraph*{cyrus.conf}\mbox{}\\
235 To support POP3/IMAP on ports 110/143 with STARTTLS add
236 \begin{lstlisting}[breaklines]
237 imap cmd="imapd" listen="imap" prefork=3
238 pop3 cmd="pop3d" listen="pop3" prefork=1
240 to the SERVICES section.\\
242 To support POP3S/IMAPS on ports 995/993 add
243 \begin{lstlisting}[breaklines]
244 imaps cmd="imapd -s" listen="imaps" prefork=3
245 pop3s cmd="pop3d -s" listen="pop3s" prefork=1
248 \paragraph*{Limitations}\mbox{}\\
250 cyrus-imapd currently (2.4.17, trunk) does not support elliptic curves. ECDHE will not work even if defined in your cipher list.
252 Currently there is no way to prefer server ciphers or to disable compression.\\
254 There is a working patch for all three features:
255 \url{https://bugzilla.cyrusimap.org/show_bug.cgi?id=3823}\\
257 There is no way to prevent unencrypted connections on the STARTTLS ports. You can prevent usage of plaintext login by setting
258 \begin{lstlisting}[breaklines]
261 in imapd.conf. But note that SASL PLAIN/LOGIN is still available!\\
266 % XXX config von Adi?
268 % ciphers = EDH+CAMELLIA256:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:-AES128:!CAMELLIA128:!ECDSA:AES256-SHA:EDH+AES128;
269 % options = CIPHER_SERVER_PREFERENCE
272 \subsubsection{SMTP in general}
274 SMTP usually uses opportunistic TLS. This means that an MTA will accept TLS connections when asked for it during handshake but will not require it. One should always support incoming opportunistic TLS and always try TLS handshake outgoing.\\
276 Furthermore a mailserver can operate in three modes:
278 \item As MSA (Mail Submission Agent) your mailserver receives mail from your clients MUAs (Mail User Agent).
279 \item As receiving MTA (Mail Transmission Agent, MX)
280 \item As sending MTA (SMTP client)
283 We recommend the following basic setup for all modes:
285 \item correctly setup MX, A and PTR RRs without using CNAMEs at all.
286 \item enable encryption (opportunistic TLS)
287 \item do not use self signed certificates
290 For SMTP client mode we additionally recommend:
292 \item the hostname used as HELO must match the PTR RR
293 \item setup a client certificate (most server certificates are client certificates as well)
294 \item either the common name or at least an alternate subject name of your certificate must match the PTR RR
295 \item do not modify the cipher suite for client mode
298 For MSA operation we recommend:
300 \item listen on submission port 587
301 \item enforce SMTP AUTH even for local networks
302 \item do not allow SMTP AUTH on unencrypted connections
303 \item optionally use the recommended cipher suites if (and only if) all your connecting MUAs support them
308 Note that (with the exception of MSA mode), it might be better to allow any cipher suite -- since any encryption is better than no encryption when it comes to opportunistic TLS.
311 \subsubsection{Postfix}
315 First, you need to generate Diffie Hellman parameters (please first take a look at the section \ref{section:PRNG}):
317 \todo{FIXME: this is a really weak setting! See also: http://postfix.1071664.n5.nabble.com/postfix-hardening-what-can-we-do-td61874.html}
318 \begin{lstlisting}[breaklines]
319 % openssl gendh -out /etc/postfix/dh_param_512.pem -2 512
320 % openssl gendh -out /etc/postfix/dh_param_1024.pem -2 1024
323 Next, we specify these DH parameters in the postfix config file:
325 \begin{lstlisting}[breaklines]
326 smtpd_tls_dh512_param_file = /etc/postfix/dh_param_512.pem
327 smtpd_tls_dh1024_param_file = /etc/postfix/dh_param_1024.pem
330 You usually don't want restrictions on the ciphers for opportunistic
331 encryption, because any encryption is better than plain text.
333 For submission (Port 587) or other special cases, however, you want to
334 enforce strong encryption. In addition to the below entries in
335 main.cf, you need to enable ``mandatory`` encryption for the
336 respective service, e.g. by adding ``-o
337 smtpd\_tls\_security\_level=encrypt'' to the submission smtpd in
340 % don't -- this influences opportunistic encryption
341 % smtpd_tls_protocols = !SSLv2, !SSLv3
343 \begin{lstlisting}[breaklines]
344 smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
345 tls_ssl_options=NO_COMPRESSION
346 smtpd_tls_mandatory_ciphers=high
347 tls_high_cipherlist='EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH+CAMELLIA256:EECDH:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:!AES128:!CAMELLIA128:!ECDSA:AES256-SHA'
348 tls_preempt_cipherlist = yes
349 tls_random_source = dev:/dev/urandom
350 %% NOTE: might want to have /dev/random here + Haveged
353 For those users, who want to use ECC key exchange, it is possible to specify this via:
354 \begin{lstlisting}[breaklines]
355 smtpd_tls_eecdh_grade = ultra
358 You can check the settings by specifying smtpd\_tls\_loglevel = 1 and then check the selected ciphers with the following command:
359 \begin{lstlisting}[breaklines]
360 $ zegrep "TLS connection established from.*with cipher" /var/log/mail.log | \
361 > awk '{printf("%s %s %s %s\n", $12, $13, $14, $15)}' | sort | uniq -c | sort -n
362 1 SSLv3 with cipher DHE-RSA-AES256-SHA
363 23 TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384
364 60 TLSv1 with cipher ECDHE-RSA-AES256-SHA
365 270 TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384
366 335 TLSv1 with cipher DHE-RSA-AES256-SHA
369 To use outgoing opportunistic TLS in postfix
371 \begin{lstlisting}[breaklines]
372 smtp_tls_note_starttls_offer = yes¬
373 smtp_tls_security_level = may¬
377 Source: \url{http://www.postfix.org/TLS_README.html}
379 \paragraph*{Limitations}\mbox{}\\
381 tls\_ssl\_options is supported from Postfix 2.11 onwards. You can
382 leave the statement in the configuration for older versions, it will
385 tls\_preempt\_cipherlist is supported from Postfix 2.8 onwards. Again,
386 you can leave the statement in for older versions.
389 \subsubsection{Exim (based on 4.82)}
391 It is highly recommended to read
393 \url{http://exim.org/exim-html-current/doc/html/spec_html/ch-encrypted_smtp_connections_using_tlsssl.html}
399 \subparagraph*{server mode (incoming)}\mbox{}\\
401 In the main config section of exim add:
403 \begin{lstlisting}[breaklines]
404 tls_certificate = ..../cert.pem
405 tls_privatekey = ..../cert.key
407 don't forget to add intermediate certificates to the .pem file if needed.\\
409 Tell exim to advertise STARTTLS in the EHLO answer:
410 \begin{lstlisting}[breaklines]
411 tls_advertise_hosts = *
414 If you want to support legacy SMTPS on port 465, and STARTTLS on smtp(25)/submission(587) ports set
415 \begin{lstlisting}[breaklines]
416 daemon_smtp_ports = smtp : smtps : submission
417 tls_on_connect_ports = 465
420 Exim already disables SSLv2 by default. We recommend to add
421 \begin{lstlisting}[breaklines]
422 openssl_options = +no_sslv2 +no_compression +cipher_server_preference
425 It is not advisable to restrict the default cipher list for opportunistic encryption as used by SMTP. Do not use cipher lists recommended for HTTPS! If you still want to define one please consult the Exim documentation or ask on the exim-users mailinglist.\\
426 % Exim maintainers do not recommend to change default ciphers
429 %\begin{lstlisting}[breaklines]
430 % tls_require_ciphers = <...recommended ciphersuite...>
433 If you want to request and verify client certificates from sending hosts set
434 \begin{lstlisting}[breaklines]
435 tls_verify_certificates = /etc/pki/tls/certs/ca-bundle.crt
436 tls_try_verify_hosts = *
439 tls\_try\_verify\_hosts only reports the result to your logfile. If you want to disconnect such clients you have to use
440 \begin{lstlisting}[breaklines]
444 You do not need to set dh\_parameters. exim with OpenSSL uses a 2048bit default prime defined in section 2.2 of RFC 5114.
445 If you want to set your own DH parameters please read the TLS documentation of exim.\\
447 The cipher used is written to the logfiles by default. You may want to add
448 \begin{lstlisting}[breaklines]
449 log_selector = <....whatever your log_selector already contains...> \
450 +tls_certificate_verified +tls_peerdn +tls_sni
452 to get even more information logged.
454 \subparagraph*{client mode (outgoing)}\mbox{}\\
456 Exim uses opportunistic encryption in the SMTP transport by default.
458 Client mode settings have to be done in the configuration section of the smtp transport (driver = smtp).
460 If you want to use a client certificate (most server certificates can be used as client certificate, too) set
461 \begin{lstlisting}[breaklines]
462 tls_certificate = .../cert.pem
463 tls_privatekey = .../cert.key
465 This is recommended for MTA-MTA traffic.\\
467 %If you want to limit used ciphers set
468 %\begin{lstlisting}[breaklines]
469 % tls_require_ciphers = <...recommended ciphersuite...>
471 % Exim Maintainers do not recommend ciphers. We shouldn't do so, too.
472 Do not limit ciphers without a very good reason. In the worst case you end up without encryption at all instead of some weak encryption. Please consult the Exim documentation if you really need to define ciphers.
474 \paragraph*{GnuTLS}\mbox{}\\
476 GnuTLS is different in only some respects to OpenSSL:
478 \item tls\_require\_ciphers needs a GnuTLS priority string instead of a cipher list. It is recommended to use the defaults by not defining this option. It highly depends on the version of GnuTLS used. Therefore it is not advisable to change the defaults.
479 \item There is no option like openssl\_options
482 \paragraph*{Limit SMTP AUTH to SSL connections only}\mbox{}\\
484 It is highly recommended to limit SMTP AUTH to SSL connections only. To do so add
485 \begin{lstlisting}[breaklines]
486 server_advertise_condition = ${if eq{$tls_cipher}{}{no}{yes}}
488 to every authenticator defined.
490 \paragraph*{Exim string expansion}\mbox{}\\
492 Note that most of the options accept expansion strings. This way you can eg. set cipher lists or STARTTLS advertisment conditionally. Please follow the link to the official Exim documentation to get more information.
494 \paragraph*{Limitations}\mbox{}\\
496 Exim currently (4.82) does not support elliptic curves with OpenSSL. This means that ECDHE is not used even if defined in your cipher list.
497 There already is a working patch to provide support:\\
498 \url{http://bugs.exim.org/show_bug.cgi?id=1397}
501 % do we need to documment starttls in detail?
502 %\subsubsection{starttls?}
506 \begin{lstlisting}[breaklines]
508 PermitEmptyPasswords no
511 HostKey /etc/ssh/ssh_host_rsa_key
513 MACs hmac-sha2-512,hmac-sha2-256,hmac-ripemd160
514 KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
517 % XXX: curve25519-sha256@libssh.org only available upstream(!)
518 Note: older linux systems won't support SHA2, PuTTY does not support RIPE-MD160.
523 \todo{write this subsection}
524 \subsubsection{IPSec}
526 \todo{cm: check if there are downgrade attacks for checkpoint \& co} \\
527 \todo{cm: reference the paper describing how complex IPSec is and that it can't be checked properly} \\
528 \todo{cm: change this to a table format: Variant ((A,B), (recommendations, recommendations))} \\
530 \paragraph*{Assumptions}\mbox{}\\
532 We assume the usage of IKE (v1 or v2) for this document, and ESP.
534 \paragraph*{Authentication}\mbox{}\\
536 IPSEC authentication should optimally be performed via RSA signatures,
537 with a key size of 2048 bits or more. Configuring only the trusted CA
538 that issued the peer certificate provides for additional protection
539 against fake certificates.
541 If you need to use Pre-Shared Key authentication:
544 \item Choose a \textbf{random} PSK of 20 characters or more (\todo{length, references!})
545 \item Use a \textbf{separate} PSK for any IPSEC connection
546 \item Change the PSKs regularily
549 \paragraph*{Cryptographic Suites}\mbox{}\\
551 IPSEC Cryptographic Suites are pre-defined settings for all the
552 items of a configuration; they try to provide a balanced security
553 level and make setting up VPNs easier.
555 When using any of those suites, make sure to enable ``Perfect Forward
556 Secrecy`` for Phase 2, as this is not specified in the suites.
558 \verb|Suite-B-GCM-256| \footnote{\url{http://tools.ietf.org/html/rfc6379}}
559 would be roughly equivalent to ``Configuration A``, but keep in mind
560 that it uses NIST elliptic curves for the Diffie-Hellman key exchange.
562 \verb|Suite-B-GCM-128| or
563 \verb|VPN-B| \footnote{\url{http://tools.ietf.org/html/rfc4308}} would
564 be roughly equivalent to ``Configuration B``; again,
565 \verb|Suite-B-GCM-128| uses NIST elliptic curves, \verb|VPN-B| does
568 \todo{Aaron: make an example for how to include images}
569 \todo{cm: screenshots of Checkpoint settings}
571 \paragraph*{IKE or Phase 1}\mbox{}\\
573 IKE or Phase 1 is the mutual authentication and key exchange phase.
575 Use only ``main mode``, as ``aggressive mode`` has known security
576 vulnerabilities \footnote{\url{http://ikecrack.sourceforge.net/}}.
578 Encryption Algorithm: AES or CAMELLIA
580 Hash Algorithm: SHA2-256, SHA2-384 or SHA2-512
582 DH Group: Group 14--18 (2048--8192 bit DH), or 19-21 (256--521 bit
585 Lifetime: \todo{need recommendations; 1 day seems to be common practice}
587 \todo{what about CAST?}
589 \paragraph*{ESP or Phase 2}\mbox{}\\
591 Enable ``Perfect Forward Secrecy`` with a DH Group equivalent to the
594 Encryption Algorithm: AES-GCM-16, AES-CTR, AES-CCM-16, AES-CBC, SEED
595 or CAMELLIA \todo{order of this list?}
597 Hash Algorithm: none (if using AES-GCM), HMAC-SHA-SHA256 or longer
598 \todo{what about AES-XCBC-MAC?}
600 Lifetime: \todo{need recommendations; 1--8 hours seems to be common practice}
603 \subsubsection{OpenVPN}
604 \todo{cm: please write this subsubsection}
605 \todo{WARNING - Section Writing in progress...}
606 \todo{We suppose user uses easy-rsa which is roughly used in all HOWTO}
608 \paragraph{Fine tuning at installation level}
610 When installing an OpenVPN server instance, you are probably using {\it easy-rsa} tools to generate the crypto stuff needed.
611 From the directory where you will run them, you can enhance you configuration by changing the following variables in {\it Vars}
613 \begin{lstlisting}[breaklines]
617 This will enhance the security of the key exchange steps by using RSA keys with a length of 2048 bits.
619 \todo{Shouldn't we need to reduce CA and certificate lifetime? Per default 10y!!}
622 \paragraph{Server Configuration}
624 \todo{To write - locked by David}
626 \begin{lstlisting}[breaklines]
627 cipher AES-128-CBC # AES
631 \paragraph{Client Configuration}
633 \todo{To write - locked by David}
635 \begin{lstlisting}[breaklines]
642 \todo{cm: please write this subsubsection}
644 \subsubsection{Cisco IPSec}
645 \todo{write this subsubsection}
647 \subsubsection{Juniper VPN}
648 \todo{write this subsubsection. AK: ask Hannes}
650 \subsubsection{L2TP over IPSec}
651 \todo{write this subsubsection}
653 \subsubsection{Racoon}
654 \todo{write this subsubsection}
657 \subsection{PGP/ GPG - Pretty Good Privacy}
659 \todo{re-work this subsection -- this is still only a draft!!}
662 \subsection{seclayer-tcp}
663 \todo{Ramin: please write this section or ask Posch}
664 For the austrian citizen card....
667 seclayer-tcp 3495/udp # securitylayer over tcp
668 seclayer-tcp 3495/tcp # securitylayer over tcp
672 \subsection{IPMI, ILO and other lights out management solutions}
673 \todo{write this!! Recommendation. Empfehlung: nie ins Internet, nur in ein eigenes mgmt VLAN, das via VPN erreichbar ist!!
677 \todo{AK: ask Klaus. Write this section, Klaus??? }
679 \subsection{Instant Messaging Systems}
680 \subsubsection{XMPP / Jabber}
683 \subsection{Intercepting proxy solutions}
685 \input{proxy_solutions}
689 %\subsection{Database Systems}
690 %\subsubsection{MySQL}
692 %\paragraph*{my.cnf}\mbox{}\\
694 %%Tested with Debian 7.0 and MySQL 5.5
696 %\begin{lstlisting}[breaklines]
699 %ssl-ca=/etc/mysql/ssl/ca-cert.pem
700 %ssl-cert=/etc/mysql/ssl/client-cert.pem
701 %ssl-key=/etc/mysql/ssl/client-key.pem
702 %ssl-cipher=EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH+CAMELLIA256:EECDH:EDH+aRSA:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED:!AES128:!CAMELLIA128:!ECDSA:AES256-SHA
705 %After restarting the server run the following query to see if the ssl settings are correct:
706 %\begin{lstlisting}[breaklines]
707 %show variables like '%ssl%';
714 %%% TeX-master: "applied-crypto-hardening"