CompTIA CompTIA Certifications CS0-003 Questions & Answers

• Question 151:

  While reviewing the web server logs a security analyst notices the following snippet ..\../..\../boot.ini

  Which of the following is being attempted?

  A. Directory traversal

  B. Remote file inclusion

  C. Cross-site scripting

  D. Remote code execution

  E. Enumeration of/etc/pasawd

  Correct Answer: A

  The log entry "......\boot.ini" is indicative of a directory traversal attack, where an attacker attempts to access files and directories that are stored outside the web root folder.

  The log snippet "......\boot.ini" is indicative of a directory traversal attack. This type of attack aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with "../" (dot-dot-slash), the attacker may be able to access arbitrary files and directories stored on the file system.

• Question 152:

  While a security analyst for an organization was reviewing logs from web servers. the analyst found several successful attempts to downgrade HTTPS sessions to use cipher modes of operation susceptible to padding oracle attacks. Which of the following combinations of configuration changes should the organization make to remediate this issue? (Select two).

  A. Configure the server to prefer TLS 1.3.

  B. Remove cipher suites that use CBC.

  C. Configure the server to prefer ephemeral modes for key exchange.

  D. Require client browsers to present a user certificate for mutual authentication.

  E. Configure the server to require HSTS.

  F. Remove cipher suites that use GCM.

  Correct Answer: AB

  A padding oracle attack is a type of attack that exploits the padding validation of a cryptographic message to decrypt the ciphertext without knowing the key. A padding oracle is a system that responds to queries about whether a message has a valid padding or not, such as a web server that returns different error messages for invalid padding or invalid MAC. A padding oracle attack can be applied to the CBC mode of operation, where the attacker can manipulate the ciphertext blocks and use the oracle's responses to recover the plaintext12. To remediate this issue, the organization should make the following configuration changes: Configure the server to prefer TLS 1.3. TLS 1.3 is the latest version of the Transport Layer Security protocol, which provides secure communication between clients and servers. TLS 1.3 has several security improvements over previous versions, such as: Remove cipher suites that use CBC. Cipher suites are combinations of cryptographic algorithms that specify how TLS connections are secured. Cipher suites that use CBC mode are vulnerable to padding oracle attacks, as well as other attacks such as BEAST and Lucky 13. Therefore, they should be removed from the server's configuration and replaced with cipher suites that use more secure modes of operation, such as GCM or CCM78. The other options are not effective or necessary to remediate this issue. Option C is not effective because configuring the server to prefer ephemeral modes for key exchange does not prevent padding oracle attacks. Ephemeral modes for key exchange are methods that generate temporary and random keys for each session, such as Diffie- Hellman or Elliptic Curve Diffie-Hellman. Ephemeral modes provide forward secrecy, which means that compromising the long-term keys does not affect the security of past sessions. However, ephemeral modes do not protect against padding oracle attacks, which exploit the padding validation of the ciphertext rather than the key exchange9. Option D is not necessary because requiring client browsers to present a user certificate for mutual authentication does not prevent padding oracle attacks. Mutual authentication is a process that verifies the identity of both parties in a communication, such as using certificates or passwords. Mutual authentication enhances security by preventing impersonation or spoofing attacks. However, mutual authentication does not protect against padding oracle attacks, which exploit the padding validation of the ciphertext rather than the authentication. Option E is not necessary because configuring the server to require HSTS does not prevent padding oracle attacks. HSTS stands for HTTP Strict Transport Security and it is a mechanism that forces browsers to use HTTPS connections instead of HTTP connections when communicating with a web server. HSTS enhances security by preventing downgrade or man-in-the-middle attacks that try to intercept or modify HTTP traffic. However, HSTS does not protect against padding oracle attacks, which exploit the padding validation of HTTPS traffic rather than the protocol. Option F is not effective because removing cipher suites that use GCM does not prevent padding oracle attacks. GCM stands for Galois/ Counter Mode and it is a mode of operation that provides both encryption and authentication for block ciphers, such as AES. GCM is more secure and efficient than CBC mode, as it prevents various types of attacks, such as padding oracle, BEAST, Lucky 13, and IV reuse attacks. Therefore, removing cipher suites that use GCM would reduce security rather than enhance it . References: 1 Padding oracle attack - Wikipedia 2 flast101/padding-oracle-attack-explained - GitHub 3 A Cryptographic Analysis of the TLS 1.3 Handshake Protocol | Journal of Cryptology 4 Which block cipher mode of operation does TLS 1.3 use? - Cryptography Stack Exchange 5 The Essentials of Using an Ephemeral Key Under TLS 1.3 6 Guidelines for the Selection, Configuration, and Use of ... - NIST 7 CBC decryption vulnerability - .NET | Microsoft Learn 8 The Padding Oracle Attack | Robert Heaton 9 What is Ephemeral Diffie-Hellman? | Cloudflare

  [10] What is Mutual TLS? How mTLS Authentication Works | Cloudflare [11] What is HSTS? HTTP Strict Transport Security Explained | Cloudflare [12] Galois/Counter Mode - Wikipedia [13] AES-GCM and its IV/nonce value - Cryptography Stack Exchange

• Question 153:

  Which of the following is a reason proper handling and reporting of existing evidence are important for the investigation and reporting phases of an incident response?

  A. To ensure the report is legally acceptable in case it needs to be presented in court

  B. To present a lessons-learned analysis for the incident response team

  C. To ensure the evidence can be used in a postmortem analysis

  D. To prevent the possible loss of a data source for further root cause analysis

  Correct Answer: A

• Question 154:

  A leader on the vulnerability management team is trying to reduce the team's workload by automating some simple but time-consuming tasks. Which of the following activities should the team leader consider first?

  A. Assigning a custom recommendation for each finding

  B. Analyzing false positives

  C. Rendering an additional executive report

  D. Regularly checking agent communication with the central console

  Correct Answer: D

• Question 155:

  An analyst suspects cleartext passwords are being sent over the network. Which of the following tools would best support the analyst's investigation?

  A. OpenVAS

  B. Angry IP Scanner

  C. Wireshark

  D. Maltego

  Correct Answer: C

• Question 156:

  A regulated organization experienced a security breach that exposed a list of customer names with corresponding PII data. Which of the following is the best reason for developing the organization's communication plans?

  A. For the organization's public relations department to have a standard notification

  B. To ensure incidents are immediately reported to a regulatory agency

  C. To automate the notification to customers who were impacted by the breach

  D. To have approval from executive leadership on when communication should occur

  Correct Answer: B

• Question 157:

  To minimize the impact of a security incident, a cybersecurity analyst has configured audit settings in the organization's cloud services. Which of the following security controls has the analyst configured?

  A. Preventive

  B. Corrective

  C. Directive

  D. Detective

  Correct Answer: D

• Question 158:

  An organization receives a legal hold request from an attorney. The request pertains to emails related to a disputed vendor contract. Which of the following is the best step for the security team to take to ensure compliance with the request?

  A. Publicly disclose the request to other vendors

  B. Notify the departments involved to preserve potentially relevant information

  C. Establish a chain of custody starting with the attorney's request

  D. Back up the mailboxes on the server and provide the attorney with a copy

  Correct Answer: B

  Upon receiving a legal hold notice, the first step is typically to ensure that all potentially relevant information is preserved. This usually involves notifying all custodians of the information, such as relevant departments and employees, to halt any data deletion or alteration processes that might normally occur. It's essential that they are aware of the need to preserve information related to the specific matter.

• Question 159:

  Which of the following best describes the actions taken by an organization after the resolution of an incident that addresses issues and reflects on the growth opportunities for future incidents?

  A. Lessons learned

  B. Scrum review

  C. Root cause analysis

  D. Regulatory compliance

  Correct Answer: A

• Question 160:

  Which of the following makes STIX and OpenloC information readable by both humans and machines?

  A. XML

  B. URL

  C. OVAL

  D. TAXII

  Correct Answer: A

  STIX and OpenloC are two standards for representing and exchanging cyber threat intelligence (CTI) information. STIX stands for Structured Threat Information Expression and OpenloC stands for Open Location and Identity Coordinates. Both standards use XML as the underlying data format to encode the information in a structured and machine- readable way. XML stands for Extensible Markup Language and it is a widely used standard for defining and exchanging data on the web. XML uses tags, attributes, and elements to describe the structure and meaning of the data. XML is also human-readable, as it uses plain text and follows a hierarchical and nested structure. XML is not the only format that can be used to make STIX and OpenloC information readable by both humans and machines, but it is the most common and widely supported one. Other formats that can be used include JSON, CSV, or PDF, depending on the use case and the preferences of the information producers and consumers. However, XML has some advantages over other formats, such as: XML is more expressive and flexible than JSON or CSV, as it can define complex data types, schemas, namespaces, and validation rules. XML is more standardized and interoperable than PDF, as it can be easily parsed, transformed, validated, and queried by various tools and languages. XML is more compatible with existing CTI standards and tools than other formats, as it is the basis for STIX 1.x, TAXII 1.x, MAEC, CybOX, OVAL, and others. References: 1 Introduction to STIX - GitHub Pages 2 5 Best Threat Intelligence Feeds in 2023 (Free and Paid Tools) - Comparitech 3 What Are STIX/TAXII Standards? - Anomali Resources 4 What is STIX/TAXII? | Cloudflare 5 Sample Use | TAXII Project Documentation - GitHub Pages 6 Trying to retrieve xml data with taxii - Stack Overflow 7 CISA AIS TAXII Server Connection Guide 8 CISA AIS TAXII Server Connection Guide v2.0 | CISA