CWE-300 Channel Accessible by Non-Endpoint

The product does not adequately verify the identity of actors at both ends of a communication channel, or does not adequately ensure the integrity of the channel, in a way that allows the channel to be accessed or influenced by an actor that is not an endpoint.

• Confidentiality, Integrity, Access Control: Read Application Data, Modify Application Data, Gain Privileges or Assume Identity — There can be misplaced trust in the entity at the other end of the channel. An attacker can interpose between the communicating entities and masquerade as the original entity. In the absence of sufficient verification of identity, such an attacker can eavesdrop and potentially modify the communication between the original entities.

• [Implementation] In order to establish secure communication between two parties, it is often important to adequately verify the identity of entities at each end of the communication channel. Always fully authenticate both ends of any communications channel. • [Architecture and Design] Adhere to the principle of complete mediation. • [Implementation] A certificate binds an identity to a cryptographic key to authenticate a communicating party. Often, the certificate takes the encrypted form of the hash of the identity of the subject, the public key, and information such as time of issue or expiration using the issuer's private key. The certificate can be validated by deciphering the certificate with the issuer's public key. See also X.509 certificate signature chains and the PGP certification structure.

• Automated Dynamic Analysis: Some tools can act as proxy servers that allow the tester to intercept packets or messages, inspect them, and modify them before sending them to the destination in order to see if the modified packets are still accepted by the receiving component. • Automated Dynamic Analysis: Dynamic Application Security Testing (DAST) tools can be used to detect network traffic without encryption and/or verification. The affected protocol may be subject to Adversary-in-the-Middle attacks. Some tools act as proxy servers that allow the tester to inspect and modify packets/messages to see if they are still accepted by the receiving component. • Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.) The analysis could identify use of protocols that are subject to Adversary-in-the-Middle attacks.

• CVE-2014-1266: Chain: incorrect "goto" in Apple SSL product bypasses certificate validation, allowing Adversary-in-the-Middle (AITM) attack (Apple "goto fail" bug). CWE-705 (Incorrect Control Flow Scoping) -> CWE-561 (Dead Code) -> CWE-295 (Improper Certificate Validation) -> CWE-393 (Return of Wrong Status Code) -> CWE-300 (Channel Accessible by Non-Endpoint). The code's whitespace indentation did not reflect the actual control flow (CWE-1114) and did not explicitly delimit the block (CWE-483), which could have made it more difficult for human code auditors to detect the vulnerability.