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DROWN Attack

A new, serious, attack on TLS and SSL has been announced. Called DROWN, it leverages a vulnerability in SSLv2 into compromise of TLS connections. This means that communications can be decrypted and read by an attacker on any affected HTTPS service.

So, if your server is configured with SSLv2 enabled, you’re vulnerable to this attack. If you’ve reused a private RSA key from a non-vulnerable server on another host running SSLv2 (even if it’s a different certificate, or different protocol like a mail server), communications with your non-vulnerable server are at risk. The solution is to disable SSLv2 on every server you control and patch OpenSSL:

OpenSSL 1.0.2 users should upgrade to 1.0.2g
OpenSSL 1.0.1 users should upgrade to 1.0.1s

The OpenSSL Security Advisory is at https://www.openssl.org/news/secadv/20160301.txt. To find out if you are vulnerable to DROWN, visit https://test.drownattack.com/ and for information about the attack visit https://drownattack.com/. To check servers manually for SSLv2 support, nmap has a script available at https://nmap.org/nsedoc/scripts/sslv2.html