Free CAS-005 Questions Attempt

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.

The best solution to reduce the likelihood of firmware-level attacks and rootkits is to implement measured boot. Measured boot is a hardware-assisted security mechanism that leverages Trusted Platform Module (TPM) and Secure Boot processes. It records cryptographic measurements of each stage of the boot process—from firmware to operating system loaders—and stores them in the TPM. Security software, such as attestation services, can then verify that the system booted into a known, trusted state. If firmware or boot-level code has been tampered with, the measurements will not match expected values, alerting administrators to compromise.

Option A (software integrity checks) validates application-level integrity but does not address firmware rootkits that load before the operating system. Option B (self-encrypting drives) protects data at rest but does not prevent rootkits. Option D (host-based encryption) ensures confidentiality but does not detect or mitigate firmware-level persistence.

Measured boot specifically targets low-level tampering, making it the most relevant control to defend against rootkits and firmware exploits.

Sinkholing, or DNS sinkholing, is a method used to redirect malicious traffic to a safe destination. This technique is often employed by security teams to prevent access to malicious domains by substituting a benign destination IP address.

In the given logs, users from the finance department are accessing and receiving HTTP status code 495. This status code is typically indicative of a client certificate error, which can occur if the DNS traffic is being manipulated or redirected incorrectly. The consistency in receiving the same HTTP status code across different users suggests a systematic issue rather than an isolated incident.

Recursive DNS resolution failure (A) would generally lead to inability to resolve DNS at all, not to a specific HTTP error.

DNS poisoning (B) could result in usersbeing directed to malicious sites, but again, would likely result in a different set of errors or unusual activity.

Incorrect DNS setup (D) would likely cause broader resolution issues rather than targeted errors like the one seen here.

By reviewing the provided data, it is evident that the DNS traffic for is being rerouted improperly, resulting in consistent HTTP 495 errors for the finance department users. Hence, the most likely cause is that the DNS traffic is being sinkholed.