CompTIA CAS-004 Exam Dumps - Valid Questions Answers

OCSP stapling is a solution that allows the web server to provide a time-stamped OCSP response signed by the CA along with the certificate during the TLS handshake, eliminating the need for the client to contact the CA separately to validate the certificate. OCSP stapling can reduce the delay caused by the certificate validation process by saving a round-trip between the client and the CA. It can also improve the security and privacy of the certificate validation by preventing potential attacks or tracking by malicious third parties. Verified References:

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

https://www.digicert.com/knowledgebase/ssl-certificates/ssl-general-topics/what-is-ocsp-stapling.html

https://www.entrust.com/knowledgebase/ssl/online-certificate-status-protocol-ocsp-stapling

OPC (Open Platform Communications) and Modbus are two common protocols used for industrial control systems (ICS). OPC is a standard that allows different devices and applications to exchange data in a vendor-neutral way. Modbus is a serial communication protocol that enables devices to send and receive commands and data over a network. Modbus has two variants: Modbus TCP/IP, which uses TCP port 502 for communication, and Modbus RTU/ASCII, which uses serial ports.

To allow an OPC server to communicate with a Modbus server that is controlling electrical relays, the security engineer should recommend restricting inbound traffic so that only the OPC server is permitted to reach the Modbus server on port 502. This configuration would:

Permit the OPC server to send commands and data to the Modbus server using Modbus TCP/IP protocol over port 502.

Limit operational disruptions, by preventing unauthorized or malicious access to the Modbus server from other sources.

Due to the limitations within the Modbus protocol, such as lack of encryption and authentication, restricting inbound traffic is a necessary security measure to protect the integrity and availability of the ICS.

Deploying a web application firewall (WAF) signature is a way to detect and block attempts to exploit the Heartbleed vulnerability on the web server. A WAF signature is a pattern that matches a known attack vector, such as a malicious heartbeat request. By deploying a WAF signature, the company can protect its web application from Heartbleed attacks until the underlying vulnerability is fixed.

Updating the OpenSSL library is the ultimate way to fix and mitigate the Heartbleed vulnerability. The OpenSSL project released version 1.0.1g on April 7, 2014, which patched the bug by adding a bounds check to the heartbeat function. By updating the OpenSSL library on the web server, the company can eliminate the vulnerability and prevent any future exploitation.

B. Fixing the PHP code is not a way to resolve or mitigate the Heartbleed vulnerability, because the vulnerability is not in the PHP code, but in the OpenSSL library that handles the SSL/TLS encryption for the web server.

C. Changing the web server from HTTPS to HTTP is not a way to resolve or mitigate the Heartbleed vulnerability, because it would expose all the web traffic to eavesdropping and tampering by attackers. HTTPS provides confidentiality, integrity, and authentication for web communications, and should not be disabled for security reasons.

D. Using SSLv3 is not a way to resolve or mitigate the Heartbleed vulnerability, because SSLv3 is an outdated and insecure protocol that has been deprecated and replaced by TLS. SSLv3 does not support modern cipher suites, encryption algorithms, or security features, and is vulnerable to various attacks, such as POODLE.

E. Changing the code from PHP to ColdFusion is not a way to resolve or mitigate the Heartbleed vulnerability, because the vulnerability is not related to the programming language of the web application, but to the OpenSSL library that handles the SSL/TLS encryption for the web server.

https://owasp.org/www-community/vulnerabilities/Heartbleed_Bug

https://heartbleed.com/