How to disable SSLv3 with Haproxy

PiBa

Hi Sebasb,

Try adding "-servername snihost" on those commands as currently no sni information is send you will end up on the default server every time. Also make sure the backend webserver that is connected over 'mode tcp' properly blocks SSLv3.. As the default bind options for certificates have no use if haproxy doesnt perform the offloading itself.

Are you sure the 'TCPFrontendPort' is forwarded through a backend to the haproxy SSLOffloadingPort ?

Can you share the haproxy.cfg you are using to validate its behavior.?.

Regards,
PiBa-NL

AlexVallois

Hi PiBa,

thank you for your feedback.

I am using TCP mode. The webserver is properly configured to not support SSLv3. When I run sslscan directly on webserver I can see that SSLv3 is properly rejected.

Please find below the complete configuration. I hope it may help to identify where my issue is. Thank you in advance for your help !

global
    maxconn            50
    stats socket /tmp/haproxy.socket level admin
    uid            80
    gid            80
    nbproc            1
    chroot            /tmp/haproxy_chroot
    daemon
    tune.ssl.default-dh-param    2048
    ssl-default-bind-options no-sslv3 no-tlsv10
    ssl-default-bind-ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK
    # Time-to-first-Byte (TTFB) value needs to be optimized based on
    # the actual public certificate chain see
    # https://www.igvita.com/2013/10/24
    # /optimizing-tls-record-size-and-buffering-latency/
    tune.ssl.maxrecord 1370

listen HAProxyLocalStats
    bind 127.0.0.1:2200 name localstats
    mode http
    stats enable
    stats admin if TRUE
    stats uri /haproxy/haproxy_stats.php?haproxystats=1
    timeout client 5000
    timeout connect 5000
    timeout server 5000

frontend abc-https-merged
    bind            192.168.0.223:443 name 192.168.0.223:443   
    mode            tcp
    log            global
    option            socket-stats
    timeout client        30000
    tcp-request inspect-delay    5s
    acl            abc    req.ssl_sni -i www.abc.com
    acl            123    req.ssl_sni -i www.123.com
    tcp-request content accept if { req.ssl_hello_type 1 }

    use_backend abc-ki-https_https_ipvANY  if  abc
    use_backend abc-ki-https_https_ipvANY  if  123
    default_backend default-https_https_ipvANY

frontend abc-efg-http-merged
    bind            192.168.0.223:80 name 192.168.0.223:80   
    mode            http
    log            global
    option            socket-stats
    option            http-keep-alive
    option            forwardfor
    acl https ssl_fc
    http-request set-header        X-Forwarded-Proto http if !https
    http-request set-header        X-Forwarded-Proto https if https
    timeout client        30000
    redirect scheme https code 301 if { hdr(Host) -i www.abc.com } !{ ssl_fc }
    acl            abc    hdr(host) -i www.abc.com
    acl            efg    hdr(host) -i www.efg.fr
    acl            456    hdr(host) -i 456.fr
    acl            123    hdr(host) -i www.123.com
    use_backend enel-efg-ki-http_http_ipvANY  if  abc
    use_backend enel-efg-ki-http_http_ipvANY  if  efg
    use_backend 456-http_http_ipvANY  if  456
    use_backend enel-efg-ki-http_http_ipvANY  if  123
    default_backend default-http_http_ipvANY

backend abc-ki-https_https_ipvANY
    mode            tcp
    log            global
    balance            source
    timeout connect        30000
    timeout server        30000
    retries            3
    option            httpchk OPTIONS /
    server            LINUX01 192.168.153.1:443 check-ssl check inter 60000  verify none

backend default-https_https_ipvANY
    mode            tcp
    log            global
    balance            source
    timeout connect        30000
    timeout server        30000
    retries            3
    option            httpchk OPTIONS /
    server            LINUX02 192.168.152.1:443 check-ssl check inter 60000  verify none

backend enel-efg-ki-http_http_ipvANY
    mode            http
    log            global
    balance            source
    timeout connect        30000
    timeout server        30000
    retries            3
    option            httpchk OPTIONS /
    server            LINUX01 192.168.153.1:80 check inter 60000  

backend 456-http_http_ipvANY
    mode            http
    log            global
    balance            source
    timeout connect        30000
    timeout server        30000
    retries            3
    option            httpchk OPTIONS /
    server            LINUX02 192.168.152.1:80 check inter 60000  

backend default-http_http_ipvANY
    mode            http
    log            global
    timeout connect        30000
    timeout server        30000
    retries            3
    option            httpchk OPTIONS /
    server            LINUX02 192.168.152.1:80 check inter 1000

Alex

@PiBa:

Your setting seems to be the right one.
Ive tried to reproduce your results.. But it seems to block all sslv3 as advertised..

You are offloading on haproxy itself? Not passing requests to the backend in tcp mode.?.
I cant tell as the config you show doesn't show the bind on port 443 your testing against..

Below my config / results..

[2.3.2-DEVELOPMENT][root@pfSense.localdomain]/root: sslscan --ssl3 192.168.0.133:587 | grep SSLv3
    Failed    SSLv3  256 bits  ECDHE-RSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ECDHE-ECDSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ECDHE-RSA-AES256-SHA384
    Failed    SSLv3  256 bits  ECDHE-ECDSA-AES256-SHA384
    Rejected  SSLv3  256 bits  ECDHE-RSA-AES256-SHA
    Rejected  SSLv3  256 bits  ECDHE-ECDSA-AES256-SHA
    Failed    SSLv3  256 bits  SRP-DSS-AES-256-CBC-SHA
    Failed    SSLv3  256 bits  SRP-RSA-AES-256-CBC-SHA
    Failed    SSLv3  256 bits  SRP-AES-256-CBC-SHA
    Failed    SSLv3  256 bits  DHE-DSS-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  DHE-RSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  DHE-RSA-AES256-SHA256
    Failed    SSLv3  256 bits  DHE-DSS-AES256-SHA256
    Rejected  SSLv3  256 bits  DHE-RSA-AES256-SHA
    Rejected  SSLv3  256 bits  DHE-DSS-AES256-SHA
    Rejected  SSLv3  256 bits  DHE-RSA-CAMELLIA256-SHA
    Rejected  SSLv3  256 bits  DHE-DSS-CAMELLIA256-SHA
    Rejected  SSLv3  256 bits  AECDH-AES256-SHA
    Failed    SSLv3  256 bits  ADH-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ADH-AES256-SHA256
    Rejected  SSLv3  256 bits  ADH-AES256-SHA
    Rejected  SSLv3  256 bits  ADH-CAMELLIA256-SHA
    Failed    SSLv3  256 bits  ECDH-RSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ECDH-ECDSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ECDH-RSA-AES256-SHA384
    Failed    SSLv3  256 bits  ECDH-ECDSA-AES256-SHA384
    Rejected  SSLv3  256 bits  ECDH-RSA-AES256-SHA
    Rejected  SSLv3  256 bits  ECDH-ECDSA-AES256-SHA
    Failed    SSLv3  256 bits  AES256-GCM-SHA384
    Failed    SSLv3  256 bits  AES256-SHA256
    Rejected  SSLv3  256 bits  AES256-SHA
    Rejected  SSLv3  256 bits  CAMELLIA256-SHA
    Failed    SSLv3  256 bits  PSK-AES256-CBC-SHA
    Failed    SSLv3  128 bits  ECDHE-RSA-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  ECDHE-ECDSA-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  ECDHE-RSA-AES128-SHA256
    Failed    SSLv3  128 bits  ECDHE-ECDSA-AES128-SHA256
    Rejected  SSLv3  128 bits  ECDHE-RSA-AES128-SHA
    Rejected  SSLv3  128 bits  ECDHE-ECDSA-AES128-SHA
    Failed    SSLv3  128 bits  SRP-DSS-AES-128-CBC-SHA
    Failed    SSLv3  128 bits  SRP-RSA-AES-128-CBC-SHA
    Failed    SSLv3  128 bits  SRP-AES-128-CBC-SHA
    Failed    SSLv3  128 bits  DHE-DSS-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  DHE-RSA-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  DHE-RSA-AES128-SHA256
    Failed    SSLv3  128 bits  DHE-DSS-AES128-SHA256
    Rejected  SSLv3  128 bits  DHE-RSA-AES128-SHA
    Rejected  SSLv3  128 bits  DHE-DSS-AES128-SHA
    Rejected  SSLv3  128 bits  DHE-RSA-SEED-SHA
    Rejected  SSLv3  128 bits  DHE-DSS-SEED-SHA
    Rejected  SSLv3  128 bits  DHE-RSA-CAMELLIA128-SHA
    Rejected  SSLv3  128 bits  DHE-DSS-CAMELLIA128-SHA
    Rejected  SSLv3  128 bits  AECDH-AES128-SHA
    Failed    SSLv3  128 bits  ADH-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  ADH-AES128-SHA256
    Rejected  SSLv3  128 bits  ADH-AES128-SHA
    Rejected  SSLv3  128 bits  ADH-SEED-SHA
    Rejected  SSLv3  128 bits  ADH-CAMELLIA128-SHA
    Failed    SSLv3  128 bits  ECDH-RSA-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  ECDH-ECDSA-AES128-GCM-SHA256
    Failed    SSLv3  128 bits  ECDH-RSA-AES128-SHA256
    Failed    SSLv3  128 bits  ECDH-ECDSA-AES128-SHA256
    Rejected  SSLv3  128 bits  ECDH-RSA-AES128-SHA
    Rejected  SSLv3  128 bits  ECDH-ECDSA-AES128-SHA
    Failed    SSLv3  128 bits  AES128-GCM-SHA256
    Failed    SSLv3  128 bits  AES128-SHA256
    Rejected  SSLv3  128 bits  AES128-SHA
    Rejected  SSLv3  128 bits  SEED-SHA
    Rejected  SSLv3  128 bits  CAMELLIA128-SHA
    Rejected  SSLv3  128 bits  IDEA-CBC-SHA
    Failed    SSLv3  128 bits  PSK-AES128-CBC-SHA
    Rejected  SSLv3  128 bits  ECDHE-RSA-RC4-SHA
    Rejected  SSLv3  128 bits  ECDHE-ECDSA-RC4-SHA
    Rejected  SSLv3  128 bits  AECDH-RC4-SHA
    Rejected  SSLv3  128 bits  ADH-RC4-MD5
    Rejected  SSLv3  128 bits  ECDH-RSA-RC4-SHA
    Rejected  SSLv3  128 bits  ECDH-ECDSA-RC4-SHA
    Rejected  SSLv3  128 bits  RC4-SHA
    Rejected  SSLv3  128 bits  RC4-MD5
    Failed    SSLv3  128 bits  PSK-RC4-SHA
    Rejected  SSLv3  112 bits  ECDHE-RSA-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  ECDHE-ECDSA-DES-CBC3-SHA
    Failed    SSLv3  112 bits  SRP-DSS-3DES-EDE-CBC-SHA
    Failed    SSLv3  112 bits  SRP-RSA-3DES-EDE-CBC-SHA
    Failed    SSLv3  112 bits  SRP-3DES-EDE-CBC-SHA
    Rejected  SSLv3  112 bits  EDH-RSA-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  EDH-DSS-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  AECDH-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  ADH-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  ECDH-RSA-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  ECDH-ECDSA-DES-CBC3-SHA
    Rejected  SSLv3  112 bits  DES-CBC3-SHA
    Failed    SSLv3  112 bits  PSK-3DES-EDE-CBC-SHA
    Rejected  SSLv3  0 bits    ECDHE-RSA-NULL-SHA
    Rejected  SSLv3  0 bits    ECDHE-ECDSA-NULL-SHA
    Rejected  SSLv3  0 bits    AECDH-NULL-SHA
    Rejected  SSLv3  0 bits    ECDH-RSA-NULL-SHA
    Rejected  SSLv3  0 bits    ECDH-ECDSA-NULL-SHA
    Failed    SSLv3  0 bits    NULL-SHA256
    Rejected  SSLv3  0 bits    NULL-SHA
    Rejected  SSLv3  0 bits    NULL-MD5

And config:

global
	maxconn			504
	log			192.168.0.40	local0	info
	stats socket /tmp/haproxy.socket level admin
	gid			80
	nbproc			1
	chroot			/tmp/haproxy_chroot
	daemon
	tune.ssl.default-dh-param	1024
	log-send-hostname		ItsMe
	lua-load		/var/etc/haproxy/luascript_acmeclient
	
	   ssl-default-bind-options no-sslv3 no-tlsv10
	   ssl-default-bind-ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK
	   # Time-to-first-Byte (TTFB) value needs to be optimized based on
	   # the actual public certificate chain see
	   # https://www.igvita.com/2013/10/24
	   # /optimizing-tls-record-size-and-buffering-latency/
	   tune.ssl.maxrecord 1370

listen HAProxyLocalStats
	bind 127.0.0.1:2200 name localstats
	mode http
	stats enable
	stats refresh 5
	stats admin if TRUE
	stats uri /haproxy/haproxy_stats.php?haproxystats=1
	timeout client 5000
	timeout connect 5000
	timeout server 5000

mailers globalmailers
	mailer EX 192.168.0.40:25

frontend SMTP-tls-test
	bind			192.168.0.133:587 name 192.168.0.133:587 ssl  crt /var/etc/haproxy/SMTP-tls-test.pem  
	mode			tcp
	log			global
	timeout client		30000
	default_backend pb3-smtp_https_ipvANY

backend pb3-smtp_https_ipvANY
	mode			tcp
	log			global
	# use mailers
	# level  debug 
	email-alert mailers			globalmailers
	email-alert level			debug
	email-alert from			me@me.tld
	email-alert to			you@you.tld
	email-alert myhostname			HAPmailer
	timeout connect		30000
	timeout server		30000
	retries			3
	server			pb3-smtp 192.168.0.40:25 check inter 1000  weight 1

PiBa

Hi Alex,

As you don't have any certificate configured on haproxy itself, haproxy cannot negotiate ssl, or block certain ciphers/ssl-versions in that process.. Any successful SSLv3 negotiation must be coming from the backend or perhaps the pfSense webgui, but surely not haproxy itself.

Are you sure both backend servers 192.168.153.1:443 and 192.168.152.1:443 are configured to block sslv3 ?

p.s. please put config files inside code block with the # icon :) saves some scrolling through the posts..

Regards,
PiBa-NL

AlexVallois

Hi PiBa,

Thank you very much. You got it ! My other webserver was not properly configured to deny SSLv3.
Once modified, it works fine.

However, I do not understand why it has any impact when testing SSLv3 with sslscan on the URL of the other website that was properly configured to deny SSLv3. Would it be possible to let me know ?

Thank you again for your quick and efficient help. :)

Alex

PS : previous post modified to manage code with # icon :)

PiBa

Hi Alex,

Probably the sslscan your using didn't send the sni extension, or for some reason its using a slightly different name than what you have configured in haproxy.. Ive sometimes seen that for example the port is included also when running on 443 , so the sni match would be done like "req.ssl_sni -i www.abc.com:443".

As for your sslscan sending sni extension, if you capture the traffic in wireshark and select the 'clienthello' packet. There should be a field ssl.handshake.extensions_server_name that has the sni servername in readable text, maybe its simply not sending it at all?

Regards,
PiBa-NL

AlexVallois

Hi PiBa,

Thank you. I followed your advice.

I did a Wireshark on client hello packets. Here is the result of what I observed :

for protocols TLSv1 and TLSv1.2, I can see a "Server Name Indication extension" section with a field "Server Name" defined to the correct URL.
for SSLv3 protocol, I do not see any entry in SSL section about SNI (see image attached)

Do you think it explains the behavior observed ? Maybe it explains why sslscan do not check the "right" webserver.

Thanks again PiBa.

Alex

sslscan_sslv3.png_thumb

PiBa

Hi Alex,

It seems like openssl which is used by sslscan doesnt like to send sni when using SSLv3 (SSLv3 is not really defined to support the extension very well..). http://security.stackexchange.com/a/101424 has a little info about that.

So that indeed would explain why the request would not match the sni hostname acl, and the default backend was used instead.
I assume that it was indeed the default backend that was not configured to block SSLv3?

Regards,
PiBa-NL

AlexVallois

Hi PiBa,

Thank you very much for this very clear explanation and the link provided.
You're right, I do confirm that it was the default backend that was still accepting SSLv3.

Alex

ACalcutt

Sorry to bring up an old thread, but there aren't many posts about securing HAProxy in pfsense and disabling tls ssl3/1.0/1.1. I just wanted to add a note how to fix this through the GUI in pfsense 21.02.2, which I didn't see anywhere.

The global setting mentioned above can be edited in the pfsense gui at
Services -> HAProxy ->Settings -> Global Advanced pass thru

To secure the ssl settings, go to https://ssl-config.mozilla.org/ and generate a HAProxy config, then add in to the Global Advanced pass thru settings. My settings looked like this

# intermediate configuration https://ssl-config.mozilla.org/
ssl-default-bind-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
ssl-default-bind-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
ssl-default-bind-options prefer-client-ciphers no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets

ssl-default-server-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
ssl-default-server-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
ssl-default-server-options no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets

johnpoz

I believe all you really need to do to disable ssl3 is this drop down box

Nothing wrong with tweaking the settings how you want with the manual method. But if all your looking to do is disable the old stuff and leave 1.2 and or just even 1.3 You should be able to just use the drop down.

One thing will tell you is the testing site
https://www.ssllabs.com/ssltest/

Will not give you an A+ if only have 1.3 enabled, atleast last time I checked which wasn't all that long ago - there is a thread about getting A+ rating somewhere around here I started.

That was driving me a bit nuts for awhile...

But yeah if your interested/concerned/worried about your settings the above link to testing will give you loads of info about what ciphers, etc. Do you have CAA set, do you have OSCP stapling, HSTS, etc. etc..

ACalcutt

@johnpoz

Where is that tuning setting? When I look in my HAProxy settings I don't have that.

I know about SSL Labs, which is how I saw tls 1.0 and 1.1 were enabled by default (getting a B rating). With the changes I made it only gets a A, but with intermediate settings I used that was expected.

johnpoz

What version of haproxy are you using? I'm on haproxy-devel 0.62_3 package that is 2.2.6 of haproxy.

And its listed right there where you looking on mine.

Little tweaking any you can get A+

ACalcutt

@johnpoz

I am using the non-devel haproxy 0.61_1, so that is probably the difference. I'd imagine these changes in devel will eventually make it to the non-devel version?

It seems like I could tweak this further without upgrading the haproxy package to devel so I'm going to keep it on the stable release for now, but it is good to know it might be easier in the future. I looked all over today and kept getting back to this post.