Skip to main content

Disable insecure TLS versions


The system must disable out-of-date or insecure versions of SSL and TLS protocols, algorithms and ciphers.


All communications between the client and the server should take place over channels that are protected and encrypted. In order to guarantee this, out-of-date or insecure protocols such as SSLv2, SSLv3, or TLS 1.0 and TLS 1.1 should be disabled. The latest version of TLS should be used and communications should not be allowed to fall back on insecure or unencrypted protocols.


  • CAPEC-94: Man in the Middle Attack: This type of attack targets the communication between two components (typically client and server). The attacker places themself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never observed.

  • CAPEC-117: Interception: An adversary monitors data streams to or from the target for information gathering purposes. This attack may be undertaken to solely gather sensitive information or to support a further attack against the target. This attack pattern can involve sniffing network traffic as well as other types of data streams (e.g., radio).

  • CAPEC-212: Functionality Misuse: An adversary leverages a legitimate capability of an application in such a way as to achieve a negative technical impact. The system functionality is not altered or modified but used in a way that was not intended.

  • CAPEC-216: Communication Channel Manipulation: An adversary manipulates a setting or parameter on communications channel in order to compromise its security. This can result in information exposure, insertion/removal of information from the communications stream, and/or potentially system compromise.

  • CAPEC-272: Protocol Manipulation: An adversary subverts a communications protocol to perform an attack. This type of attack targets invalid assumptions that may be inherent in implementers of the protocol, incorrect implementations of the protocol, or vulnerabilities in the protocol itself.

  • CAPEC-594: Traffic Injection: An adversary injects traffic into the target’s network connection. The adversary is therefore able to degrade or disrupt the connection, and potentially modify the content.

  • CWE-319: Cleartext Transmission of Sensitive Information: The software transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.

  • CWE-326: Inadequate Encryption Strength: The software stores or transmits sensitive data using an encryption scheme that is theoretically sound, but is not strong enough for the level of protection required.

  • Algorithm Downgrade: A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties.

  • OWASP Top 10 A3:2017-Sensitive Data Exposure: Many web applications and APIs do not properly protect sensitive data, such as financial, healthcare and PII. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft or other crimes. Sensitive data may be compromised without extra protection, such as encryption at rest or in transit, and requires special precautions when exchanged with the browser.

  • OWASP-ASVS v4.0.1 Appendix C: Internet of Things Verification Requirements.(C.22): Verify that the device cannot be downgraded to old versions (anti-rollback) of valid firmware.

  • OWASP-ASVS v4.0.1 V9.1 Communications Security Requirements.(9.1.1): Verify that secured TLS is used for all client connectivity, and does not fall back to insecure or unencrypted protocols.

  • OWASP-ASVS v4.0.1 V9.1 Communications Security Requirements.(9.1.2): Verify using online or up to date TLS testing tools that only strong algorithms, ciphers and protocols are enabled, with the strongest algorithms and ciphers set as preferred.

  • OWASP-ASVS v4.0.1 V9.1 Communications Security Requirements.(9.1.3): Verify that old versions of SSL and TLS protocols, algorithms, ciphers, and configuration are disabled, such as SSLv2, SSLv3, or TLS 1.0 and TLS 1.1. The latest version of TLS should be the preferred cipher suite.

  • OWASP-ASVS v4.0.1 V9.2 Server Communications Security Requirements.(9.2.2): Verify that encrypted communications such as TLS is used for all inbound and outbound connections, including for management ports, monitoring, authentication, API, or web service calls, database, cloud, serverless, mainframe, external and partner connections. The server must not fall back to insecure or unencrypted protocols.

  • PCI DSS v3.2.1 - Requirement 2.2.2: Enable only necessary services, protocols, daemons, etc., as required for the function of the system.

  • PCI DSS v3.2.1 - Requirement 4.1: Use strong cryptography and security protocols to safeguard sensitive cardholder data during transmission over open, public networks. The protocol in use only supports secure versions or configurations.

  • PCI DSS v3.2.1 - Requirement 6.5.4: Address common coding vulnerabilities in software-development processes such as insecure communications.

  • PCI DSS v3.2.1 - Appendix A2 A2.1: Where POS POI terminals use SSL and/or early TLS, the entity must confirm the devices are not susceptible to any known exploits for those protocols.