CAS-005 Exam Dumps : CompTIA SecurityX Certification Exam

To prevent emails from being marked as spam, several DNS records related to email authentication need to be properly configured and updated when there are changes to the email server'scertificates:

A. DMARC (Domain-based Message Authentication, Reporting & Conformance): DMARC records help email servers determine how to handle messages that fail SPF or DKIM checks, improving email deliverability and reducing the likelihood of emails being marked as spam.

B. SPF (Sender Policy Framework): SPF records specify which mail servers are authorized to send email on behalf of your domain. Updating the SPF record ensures that the new email server is recognized as an authorized sender.

C. DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to email headers, allowing the receiving server to verify that the email has not been tampered with and is from an authorized sender. Updating DKIM records ensures that emails are properly signed and authenticated.

D. DNSSEC (Domain Name System Security Extensions): DNSSEC adds security to DNS by enabling DNS responses to be verified. While important for DNS security, it does not directly address the issue of emails being marked as spam.

E. SASC: This is not a relevant standard for this scenario.

F. SAN (Subject Alternative Name): SAN is used in SSL/TLS certificates for securing multiple domain names, not for email delivery issues.

G. SOA (Start of Authority): SOA records are used for DNS zone administration and do not directly impact email deliverability.

H. MX (Mail Exchange): MX records specify the mail servers responsible for receiving email on behalf of a domain. While important, the primary issue here is the authentication of outgoing emails, which is handled by SPF, DKIM, and DMARC.

To support email authenticity and enable analysis by a third-party platform, the protocols must verify the sender’s identity and provide metadata for inspection. According to the CompTIA SecurityX CAS-005 study guide (Domain 3: Cybersecurity Technology, 3.2):

DMARC (Domain-based Message Authentication, Reporting, and Conformance):DMARC builds on SPF and DKIM to enforce policies for email authenticity and provides reporting mechanisms to share authentication results with third parties for analysis.

DKIM (DomainKeys Identified Mail):DKIM adds a cryptographic signature to emails, allowing recipients to verify the sender’s domain and ensure the email’s integrity.

These two protocols are essential for authenticity and reporting.

Option C (TLS):TLS ensures encryption during transmission but does not address authenticity or reporting.

Option D (SPF):SPF verifies sender IP addresses but lacks reporting capabilities without DMARC.

Option E (DNSSEC):DNSSEC secures DNS queries but is not specific to email authenticity.

Option F (MX):MX records define mail servers, not authenticity or reporting.

ChaCha20-Poly1305is a cipher suite specifically designed for efficiency on systems with limited hardware resources. It offers high security with lower memory and CPU consumption compared to AES on certain platforms, especially mobile devices. TLS 1.3 supports ChaCha20-Poly1305 natively. CBC (Cipher Block Chaining) modes like IDEA-CBC and Camellia-CBC are less efficient and not recommended under TLS 1.3, and AES-GCM, while secure, can be less efficient than ChaCha20 on devices without AES hardware acceleration.