CURLOPT_SSL_OPTIONS (3) - Linux Man Pages
CURLOPT_SSL_OPTIONS: set SSL behavior options
NAMECURLOPT_SSL_OPTIONS - set SSL behavior options
DESCRIPTIONPass a long with a bitmask to tell libcurl about specific SSL behaviors.
CURLSSLOPT_ALLOW_BEAST is the only supported bit and by setting this the user will tell libcurl to not attempt to use any workarounds for a security flaw in the SSL3 and TLS1.0 protocols. If this option isn't used or this bit is set to 0, the SSL layer libcurl uses may use a work-around for this flaw although it might cause interoperability problems with some (older) SSL implementations. WARNING: avoiding this work-around lessens the security, and by setting this option to 1 you ask for exactly that.