OpenSSL before 0.9.8za, 1.0.0 before 1.0.0m, and 1.0.1 before 1.0.1h does not properly restrict processing of ChangeCipherSpec messages.
Detects whether a server is vulnerable to the SSL/TLS "CCS Injection" vulnerability (CVE-2014-0224), first discovered by Masashi Kikuchi. The script is based on the ccsinjection.c code authored by Ramon de C Valle.
In order to exploit the vulnerablity, a MITM attacker would effectively do the following:
o Wait for a new TLS connection, followed by the ClientHello ServerHello handshake messages.
o Issue a CCS packet in both the directions, which causes the OpenSSL code to use a zero length pre master secret key. The packet is sent to both ends of the connection. Session Keys are derived using a zero length pre master secret key, and future session keys also share this weakness.
o Renegotiate the handshake parameters.
o The attacker is now able to decrypt or even modify the packets in transit.
The script works by sending a 'ChangeCipherSpec' message out of order and checking whether the server returns an 'UNEXPECTED_MESSAGE' alert record or not. Since a non-patched server would simply accept this message, the CCS packet is sent twice, in order to force an alert from the server. If the alert type is different than 'UNEXPECTED_MESSAGE', we can conclude the server is vulnerable.
In order to avoid exploitation from CVE-2014-0224, ensure that your system is updated to the latest version of OpenSSL.