CAPEC-217 Exploiting Incorrectly Configured SSL/TLS

An adversary takes advantage of incorrectly configured SSL/TLS communications that enables access to data intended to be encrypted. The adversary may also use this type of attack to inject commands or other traffic into the encrypted stream to cause compromise of either the client or server.

SSL/TLS communications become vulnerable to this attack when they use outdated versions and insecure ciphers. Currently, all SSL versions are deprecated and TLS versions 1.0 and 1.1 are also deprecated due to being insecure. It is still possible for later versions of TLS to be insecure if they are configured with insecure ciphers such as 3DES or RC4.

1. [Explore] [Determine SSL/TLS Configuration] Determine the SSL/TLS configuration of either the server or client being targeted, preferably both. This is not a hard requirement, as the adversary can simply assume commonly exploitable configuration settings and indiscriminately attempt them. 2. [Experiment] [Intercept Communication] Provide controlled access to the server by the client, by either providing a link for the client to click on, or by positioning one's self at a place on the network to intercept and control the flow of data between client and server, e.g. AiTM (adversary in the middle - CAPEC-94). 3. [Exploit] [Capture or Manipulate Sensitive Data] Once the adversary has the ability to intercept the secure communication, they exploit the incorrectly configured SSL to view the encrypted communication. The adversary can choose to just record the secure communication or manipulate the data to achieve a desired effect.

• Access to the client/server stream.

• [High] The adversary needs real-time access to network traffic in such a manner that the adversary can grab needed information from the SSL stream, possibly influence the decided-upon encryption method and options, and perform automated analysis to decipher encrypted material recovered. Tools exist to automate part of the tasks, but to successfully use these tools in an attack scenario requires detailed understanding of the underlying principles.

• Confidentiality: Read Data • Confidentiality, Access Control, Authorization: Gain Privileges

• Do not use SSL, as all SSL versions have been broken and should not be used. If TLS is not an option for the client or server, consider setting timeouts on SSL sessions to extremely low values to lessen the potential impact. • Only use TLS version 1.2+, as versions 1.0 and 1.1 are insecure. • Configure TLS to use secure algorithms. The current recommendation is to use ECDH, ECDSA, AES256-GCM, and SHA384 for the most security.