CAS-004 Exam Dumps - CompTIA Advanced Security Practitioner (CASP+) Exam

DMARC (Domain-based Message Authentication, Reporting and Conformance) and SPF (Sender Policy Framework) are two mechanisms that can help detect and prevent email spoofing, which is the creation of email messages with a forged sender address. DMARC allows a domain owner to publish a policy that specifies how receivers should handle messages that fail authentication tests, such as SPF or DKIM (DomainKeys Identified Mail). SPF allows a domain owner to specify which mail servers are authorized to send email on behalf of their domain. By checking the DMARC and SPF records of the sender’s domain, a receiver can verify if the email is from a legitimate source or not. Verified References:

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

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

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

The three metric groups that are needed to calculate CVSS scores are Base, Temporal, and Environmental. The Base metrics represent the intrinsic characteristics of a vulnerability that are constant over time and across user environments. The Temporal metrics represent the characteristics of a vulnerability that may change over time but not across user environments. The Environmental metrics represent the characteristics of a vulnerability that are relevant and unique to a particular user’s environment. Verified References:

https://nvd.nist.gov/vuln-metrics/cvss

https://www.first.org/cvss/specification-document

Cipher feedback (CFB) is a mode of operation for block ciphers that allows them to encrypt streaming data. CFB uses an initialization vector (IV) and a block cipher to generate a keystream that is XORed with the plaintext to produce the ciphertext. CFB has low latency because it can encrypt each byte or bit of plaintext as soon as it arrives, without waiting for a full block. CFB is suitable for streaming data because it does not require padding or block synchronization.

B. Cipher block chaining message authentication code (CBC-MAC) is a mode of operation for block ciphers that provides both encryption and authentication. CBC-MAC uses an IV and a block cipher to encrypt the plaintext and generate a MAC value that is appended to the ciphertext. CBC-MAC has high latency because it requires the entire message to be processed before generating the MAC value. CBC-MAC is not suitable for streaming data because it requires padding and block synchronization.

C. Cipher block chaining (CBC) is a mode of operation for block ciphers that provides encryption only. CBC uses an IV and a block cipher to encrypt each block of plaintext by XORing it with the previous ciphertext block. CBC has high latency because it requires a full block of plaintext before encryption. CBC is not suitable for streaming data because it requires padding and block synchronization.

D. Electronic codebook (ECB) is a mode of operation for block ciphers that provides encryption only. ECB uses a block cipher to encrypt each block of plaintext independently. ECB has low latency because it can encrypt each block of plaintext as soon as it arrives. However, ECB is not suitable for streaming data because it requires padding and block synchronization. Moreover, ECB is insecure because it does not use an IV and produces identical ciphertext blocks for identical plaintext blocks.

A regular expression (regex) is a sequence of characters that defines a search pattern for matching text. A regex can be used to detect the presence of a malicious piece of software communicating with its command-and-control server by matching the indicators of compromise (IOC) in the network traffic.

In this case, the systems administrator should use the regex Host: [a-z]*.malicious.com to determine if any of the company hosts are compromised, while reducing false positives, because this regex would:

Match the Host header in the HTTP request, which specifies the domain name of the command-and-control server.

Allow any subdomain under the malicious.com domain, by using the character class [a-z]*, which matches zero or more lowercase letters.

Escape the dot character in the domain name, by using the backslash , which prevents it from being interpreted as a wildcard that matches any character.

Not match any other parts of the IOC that could change, such as the URL path, the User-Agent header, or the HTTP method.

Executing the files in the sandbox on the web proxy is the best solution to reduce the risk of employees downloading and opening malicious files from the internet. A sandbox is a secure and isolated environment that can run untrusted or potentially harmful code without affecting the rest of the system. By executing the files in the sandbox, the web proxy can analyze their behavior and detect any malicious activity before allowing them to reach the corporate workstations.

References: [CompTIA CASP+ Study Guide, Second Edition, page 273]

The company should use an additional layer of encryption to secure the data from theft when moving to a CSP. Encryption is a process of transforming data into an unreadable format using a secret key. Encryption can protect the data from unauthorized access or modification during transit and at rest. Encryption can be applied at different levels, such as disk, file, or application. An additional layer of encryption can provide an extra security measure on top of the encryption provided by the CSP. Verified References:

https://learn.microsoft.com/en-us/partner-center/transition-seat-based-services

https://cloud.google.com/architecture/patterns-for-connecting-other-csps-with-gcp

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/

A content delivery network (CDN) is a geographically distributed network of servers that can cache content close to end users, allowing for faster and more efficient delivery of web content, such as images, videos, and streaming media. A CDN can also handle an increase in customer demand of resources, provide high-quality streaming media, and create a user-friendly interface by reducing latency and bandwidth consumption. A CDN can also improve the security and availability of the website by mitigating DDoS attacks and providing redundancy. Verified References:

https://www.cloudflare.com/learning/cdn/what-is-a-cdn/

https://learn.microsoft.com/en-us/azure/cdn/cdn-overview

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