This is a text-only version of the following page on https://raymii.org:
---
Title : Check and Fix SSL servers for SSLv3 connections or the Poodle CVE-2014-3566 bug
Author : Remy van Elst
Date : 14-10-2014
URL : https://raymii.org/s/articles/Check_servers_for_the_Poodle_bug.html
Format : Markdown/HTML
---
![poodle][1]
The POODLE bug is a new bug discovered by Google in the SSLv3 protocol. The fix
is easy, disable support for SSLv3. See <https://cipherli.st> for a good list of
SSL ciphers. You can use this check from the shell to check your servers.
This command can easily be automated with other shell scripts. It also allows
you to check your services without exposing them to an external checking
website.
See the google security blog for more info on the bug: .
<p class="ad"> <b>Recently I removed all Google Ads from this site due to their invasive tracking, as well as Google Analytics. Please, if you found this content useful, consider a small donation using any of the options below:</b><br><br> <a href="https://leafnode.nl">I'm developing an open source monitoring app called Leaf Node Monitoring, for windows, linux & android. Go check it out!</a><br><br> <a href="https://github.com/sponsors/RaymiiOrg/">Consider sponsoring me on Github. It means the world to me if you show your appreciation and you'll help pay the server costs.</a><br><br> <a href="https://www.digitalocean.com/?refcode=7435ae6b8212">You can also sponsor me by getting a Digital Ocean VPS. With this referral link you'll get $100 credit for 60 days. </a><br><br> </p>
You can use a website like <http://poodlebleed.com/> for a web based check.
### Fix POODLE
To fix the bug, disable SSLv3 and use a secure cipherlist. I've written a few
good tutorials about strong SSL security for different webservers. These
tutorials automatically fix POODLE because they disable SSLv3:
* [See my tutorial for Apache][3]
* [See my tutorial for nginx][4]
* [See my tutorial for lighttpd][5]
Want an easy, very secure copy-pastable config for your webserver? Check out my
other project, <https://cipherli.st> for a good, secure config.
If this article helped you and you want to support me AND get $10 Digital Ocean
credit (2 months free), use this link to order:
<https://www.digitalocean.com/?refcode=7435ae6b8212>
### TLS-FALLBACK-SCSV
Google have proposed an extension to SSL/TLS named [TLS _FALLBACK_ SCSV][6] that
seeks to prevent forced SSL downgrades. This is automatically enabled if you
upgrade OpenSSL to the following versions:
* OpenSSL 1.0.1 has TLS _FALLBACK_ SCSV in 1.0.1j and higher.
* OpenSSL 1.0.0 has TLS _FALLBACK_ SCSV in 1.0.0o and higher.
* OpenSSL 0.9.8 has TLS _FALLBACK_ SCSV in 0.9.8zc and higher.
### Manual check
Use the following command to check an IP or hostname:
echo | timeout 3 openssl s_client -connect HOSTNAMEORIPADDRESS:443 >/dev/null 2>&1; if [[ $? != 0 ]]; then echo "UNKNOWN: HOSTNAMEORIPADDRESS timeout or connection error"; else echo | openssl s_client -connect HOSTNAMEORIPADDRESS:443 -ssl3 2>&1 | grep -qo "sslv3 alert handshake failure\|SSL3_GET_RECORD:wrong version number" && echo "OK: HOSTNAMEORIPADDRESS Not vulnerable" || echo "FAIL: HOSTNAMEORIPADDRESS vulnerable; sslv3 connection accepted"; fi
Replace HOSTNAMEORIPADDRESS by the actual hostname or IP address. If you use
SNI, add the `-servername actualhost.org` option to the 2 OpenSSL commands, like
so:
openssl s_client -servername snihostname.org -connect 172.16.30.5:443 -ssl
### Examples
#### Non-vulnerable website:
echo | timeout 3 openssl s_client -connect raymii.org:443 >/dev/null 2>&1; if [[ $? != 0 ]]; then echo "UNKNOWN: raymii.org timeout or connection error"; else echo | openssl s_client -connect raymii.org:443 -ssl3 2>&1 | grep -qo "sslv3 alert handshake failure\|SSL3_GET_RECORD:wrong version number" && echo "OK: raymii.org Not vulnerable" || echo "FAIL: raymii.org vulnerable; sslv3 connection accepted"; fi
Result:
OK: raymii.org Not vulnerable
#### Vulnerable site:
echo | timeout 3 openssl s_client -connect sslv3-testhost.com:443 >/dev/null 2>&1; if [[ $? != 0 ]]; then echo "UNKNOWN: sslv3-testhost.com timeout or connection error"; else echo | openssl s_client -connect sslv3-testhost.com:443 -ssl3 2>&1 | grep -qo "sslv3 alert handshake failure\|SSL3_GET_RECORD:wrong version number" && echo "OK: sslv3-testhost.com Not vulnerable" || echo "FAIL: sslv3-testhost.com vulnerable; sslv3 connection accepted"; fi
Result:
FAIL: sslv3-testhost.com vulnerable; sslv3 connection accepted
#### Site without SSL:
echo | timeout 3 openssl s_client -connect pepermunt.net:443 >/dev/null 2>&1; if [[ $? != 0 ]]; then echo "UNKNOWN: pepermunt.net timeout or connection error"; else echo | openssl s_client -connect pepermunt.net:443 -ssl3 2>&1 | grep -qo "sslv3 alert handshake failure\|SSL3_GET_RECORD:wrong version number" && echo "OK: pepermunt.net Not vulnerable" || echo "FAIL: pepermunt.net vulnerable; sslv3 connection accepted"; fi
Result:
UNKNOWN: pepermunt.net timeout or connection error
You can check other ports by changing `443` to any other valid port.
[1]: https://raymii.org/s/inc/img/poodlebleed.png
[2]: https://www.digitalocean.com/?refcode=7435ae6b8212
[3]: https://raymii.org/s/tutorials/Strong_SSL_Security_On_Apache2.html
[4]: https://raymii.org/s/tutorials/Strong_SSL_Security_On_nginx.html
[5]: https://raymii.org/s/tutorials/Strong_SSL_Security_On_lighttpd.html
[6]: https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00
---
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