On-path decryption attacks, such as BEAST (Browser Exploit Against SSL/TLS) and other related vulnerabilities, often exploit weaknesses in the implementation of CBC (Cipher Block Chaining) mode. To mitigate these attacks, the following actions are recommended:
B . Removing support for CBC-based key exchange and signing algorithms: CBC mode is vulnerable to certain attacks like BEAST. By removing support for CBC-based ciphers, you can eliminate one of the primary vectors for these attacks. Instead, use modern cipher modes like GCM (Galois/Counter Mode) which offer better security properties.
C . Adding TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA256: This cipher suite uses Elliptic Curve Diffie-Hellman Ephemeral (ECDHE) for key exchange, which provides perfect forward secrecy. It also uses AES in GCM mode, which is not susceptible to the same attacks as CBC. SHA-256 is a strong hash function that ensures data integrity.
Reference:
CompTIA Security+ Study Guide
NIST SP 800-52 Rev. 2, "Guidelines for the Selection, Configuration, and Use of Transport Layer Security (TLS) Implementations" OWASP (Open Web Application Security Project) guidelines on cryptography and secure communication

Implementing security and quality checks in a CI/CD pipeline ensures that:
Container images are scanned for vulnerabilities before deployment.
Hashes validate image integrity.
Other options:
A (Configuring ACLs on mesh networks) improves access control but does not ensure scanning.
C (Audits on container images) detect changes but do not enforce best practices.
D (Pulling from a vendor repository) does not ensure vulnerability scanning.

The situation where several employees were contacted by the same individual impersonating a recruiter best describes a spear-phishing campaign. Here's why:
Targeted Approach: Spear-phishing involves targeting specific individuals within an organization with personalized and convincing messages to trick them into divulging sensitive information or performing actions that compromise security.
Impersonation: The use of impersonation, in this case, a recruiter, is a common tactic in spear-phishing to gain the trust of the targeted individuals and increase the likelihood of a successful attack.
Correlated Contacts: The fact that several employees were contacted by the same individual suggests a coordinated effort to breach the organization's security by targeting multiple points of entry through social engineering.
Reference:
CompTIA Security+ SY0-601 Study Guide by Mike Chapple and David Seidl
NIST Special Publication 800-61: Computer Security Incident Handling Guide OWASP Phishing Cheat Sheet

The most appropriate solution for the systems engineer to deploy is SELinux (Security-Enhanced Linux). Here's why:
Mandatory Access Control (MAC): SELinux enforces MAC policies, ensuring that only authorized users and processes can access specific resources. This helps in preventing unauthorized reading and modification of data and programs.
Access Vector Cache: SELinux utilizes an access vector cache (AVC) to improve performance. The AVC caches access decisions, reducing the need for repetitive policy lookups and thus improving system efficiency.
Security Mechanisms: SELinux provides a robust framework to enforce security policies and prevent bypassing of application security mechanisms. It controls access based on defined policies, ensuring that security measures are consistently applied.
Privilege Escalation and Process Interference: SELinux limits the ability of processes to escalate privileges and interfere with each other by enforcing strict access controls. This containment helps in isolating processes and minimizing the risk of privilege escalation attacks.
Reference:
CompTIA Security+ SY0-601 Study Guide by Mike Chapple and David Seidl
NSA's Guide to the Secure Configuration of Red Hat Enterprise Linux 5 (SELinux) NIST Special Publication 800-53: Security and Privacy Controls for Information Systems and Organizations

The best way to prevent application-focused attacks for a platform-as-a-service solution with a web-based front end is to create Web Application Firewall (WAF) policies for relevant programming languages. Here's why:
Application-Focused Attack Prevention: WAFs are designed to protect web applications by filtering and monitoring HTTP traffic between a web application and the Internet. They help prevent attacks such as SQL injection, cross-site scripting (XSS), and other application-layer attacks.
Customizable Rules: WAF policies can be tailored to the specific programming languages and frameworks used by the web application, providing targeted protection based on known vulnerabilities and attack patterns.
Real-Time Protection: WAFs provide real-time protection, blocking malicious requests before they reach the application, thereby enhancing the security posture of the platform.
Reference:
CompTIA Security+ SY0-601 Study Guide by Mike Chapple and David Seidl
OWASP Top Ten: Web Application Security Risks
NIST Special Publication 800-95: Guide to Secure Web Services