CVE-2017-3990 - Unpatched OpenSSL Vulnerability

OpenSSL is a widely used cryptographic library. This vulnerability allows attackers to execute arbitrary code on your server by exploiting a buffer overflow in the SSLv2 protocol. If you're using an outdated version of OpenSSL, an attacker can inject malicious data into encrypted connections, potentially leading to eavesdropping or code execution.

You're affected if you use an unpatched version of OpenSSL (versions prior to 1.0.1g). Check with: openssl s_client -connect example.com:443 -tls1.0

Note: This vulnerability is similar to CVE-2014-0160, but it's a different issue in the same library.

To fix this vulnerability:

1. Upgrade OpenSSL to version 1.0.1g or later.
2. For immediate mitigation:
3. Disable SSLv2 protocol support (openssl s_client -connect example.com:443 -no-tls1.0)
4. Use a secure cipher suite (openssl s_client -connect example.com:443 -cipher TLSv1.2)