CAS-004 Questions Bank

A downgrade attack is a type of man-in-the-middle attack that forces two hosts to use an older or weaker version of the TLS protocol or its parameters. The attacker does this by replacing or deleting the STARTTLS command or exploiting the compatibility features of the protocol. The purpose of the attack is to create a pathway for enabling a cryptographic attack that would not be possible in case of a connection that is encrypted over the latest version of TLS protocol. The IOC shows that most client connections are renegotiated after establishing the connections, which could indicate that an entity is performing downgrade attacks on path by interfering with the initial handshake and making the client and server agree on a lower version of TLS or a weaker cipher suite. Verified References:

https://en.wikipedia.org/wiki/Downgrade_attack

https://crypto.stackexchange.com/questions/10493/why-is-tls-susceptible-to-protocol-downgrade-attacks

https://venafi.com/blog/preventing-downgrade-attacks/

Law enforcement officials informed an organization that an investigation has begun. Which of the following is the FIRST step the organization should take?

Initiate a legal hold.

Refer to the retention policy

Perform e-discovery.

Review the subpoena

Answer: A

A legal hold is a process by which an organization instructs its employees or other relevant parties to preserve specific data for potential litigation. A legal hold is triggered when litigation is reasonably anticipated, such as when law enforcement officials inform an organization that an investigation has begun. The first step the organization should take is to initiate a legal hold to ensure that relevant evidence is not deleted, destroyed, or altered. A legal hold also demonstrates the organization’s good faith and compliance with its duty to preserve evidence. Verified References:

https://percipient.co/litigation-hold-triggers-and-the-duty-to-preserve-evidence/

https://www.everlaw.com/blog/ediscovery-best-practices/guide-to-legal-holds/

The company should implement OCSP stapling and HSTS to improve TLS performance and enforce HTTPS. OCSP stapling is a technique that allows a server to provide a signed proof of the validity of its certificate along with the TLS handshake, instead of relying on the client to contact the certificate authority (CA) for verification. This can reduce the latency and bandwidth of the TLS handshake, as well as improve the privacy and security of the certificate status. HSTS stands for HTTP Strict Transport Security, which is a mechanism that instructs browsers to only use HTTPS when connecting to a website, and to reject any unencrypted or invalid connections. This can prevent downgrade attacks, man-in-the-middle attacks, and mixed content errors, as well as improve the performance of HTTPS connections by avoiding unnecessary redirects. Verified References:

https://www.techtarget.com/searchsecurity/definition/OCSP-stapling

https://www.techtarget.com/searchsecurity/definition/HTTP-Strict-Transport-Security

https://www.cloudflare.com/learning/ssl/what-is-hsts/

The analyst should implement every solution one at a time in a virtual lab, running an attack simulation each time while collecting metrics. Roll back each solution and then implement the next. Choose the best solution based on the best metrics. This approach would allow the analyst to test each solution individually and measure its effectiveness against the attack, without affecting the other solutions or the production environment. This would also minimize the downtime required to implement the best solution, as only one change would be needed. The other options would either involve implementing multiple solutions at once, which could cause conflicts or errors, or collecting metrics before running the attack simulation, which would not reflect the actual impact of the solutions.