CND Practice Test 8 — 10 Questions

Question 1

An enterprise application developer is implementing JSON Web Tokens (JWT) for stateless session authentication. Which implementation flaw represents the highest risk of signature forgery and unauthorized privilege escalation?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Failing to strictly validate the JWT algorithm header, allowing 'none' or asymmetric-to-symmetric key confusion (RS256 to HS256). The JWT algorithm header (alg) is attacker-controlled and must be strictly validated server-side against an allowlist. If the application accepts 'none' or trusts the alg field to select the verification key, an attacker can forge tokens — the classic RS256-to-HS256 confusion attack lets the attacker sign with the public RSA key as an HMAC secret, which the server then accepts. This directly enables signature forgery and privilege escalation.

Answer

Setting an expiration time (exp claim) of 15 minutes

Answer

Storing the JWT inside an HTTP-only Secure cookie instead of localStorage

Answer

Including the user's role claim inside the public payload section

Question 2

An attacker targets an enterprise Active Directory domain by performing a DCSync attack, successfully replicating domain controller password data without being a domain controller. Which Active Directory access control rights must be audited and protected to prevent non-administrative users from executing DCSync?

Accepted Answer

Audit and restrict the 'Replicating Directory Changes' and 'Replicating Directory Changes All' extended access rights on the domain object.. DCSync abuses the Directory Replication Service (DRS) Remote Protocol by impersonating a domain controller and requesting password hashes via GetNCChanges. The two extended rights that grant this capability are 'Replicating Directory Changes' (DS-Replication-Get-Changes) and 'Replicating Directory Changes All' (DS-Replication-Get-Changes-All), plus 'Replicating Directory Changes In Filtered Set' in some cases. Auditing and restricting these ACEs on the domain NC head prevents non-DC principals from performing replication.

Answer

Enforce LDAP signing and channel binding on all domain controller NTDS settings.

Answer

Monitor the 'GenericAll' and 'WriteDacl' permissions on all computer account objects.

Answer

Disable NT LAN Manager (NTLM) authentication and enforce Kerberos ticket granting settings.

Question 3

A security analyst needs to configure Snort to generate an alert whenever an inbound packet matches a specific rule condition, without blocking the traffic. Which rule action keyword should be used in the Snort configuration file?

Accepted Answer

alert. The 'alert' rule action keyword in Snort generates an alert and logs the packet when a rule matches, without dropping or blocking the traffic. This is the default and most common action for intrusion detection mode. When Snort runs in IDS mode, 'alert' is the appropriate keyword to detect and notify without interfering with the packet flow.

Answer

sdrop

Answer

reject

Answer

drop

Question 4

An enterprise is drafting an Acceptable Use Policy (AUP) for employee internet and device usage. Which element is essential to include in the policy document to ensure enforceability?

Accepted Answer

Explicit notification that network activity is monitored and clear disciplinary actions for violations.. The essential element for enforceability in an AUP is explicit notification that network activity is monitored and clear disciplinary actions for violations. Without informing employees that their activity is monitored, the policy may be legally unenforceable due to privacy expectations. Clear disciplinary actions provide the necessary consequences to deter violations and ensure consistent enforcement. This combination establishes both transparency and accountability, which are fundamental to a valid AUP.

Answer

The vendor part numbers and firmware release schedules for core network switches.

Answer

The exact physical coordinates and lock combinations of the server room cages.

Answer

Detailed command-line instructions for configuring IPsec VPN tunnels on remote laptops.

Question 5

An organization is conducting a mandatory security audit for PCI-DSS compliance regarding its cardholder data environment (CDE). The auditor asks for proof of network segmentation. What should the network security administrator present?

Accepted Answer

Architecture diagrams and firewall rulebases demonstrating that out-of-scope networks cannot reach the CDE without strict filtering.. PCI-DSS segmentation evidence requires demonstrating that out-of-scope networks cannot reach the cardholder data environment (CDE) without passing through a controlled, filtered boundary. Architecture diagrams show the intended segmentation, and firewall rulebases prove the actual enforcement — together they are the standard artifacts auditors request to validate that the CDE is isolated and that all access is explicitly authorized and restricted.

Answer

Antivirus signature update logs from all workstation endpoints.

Answer

Software asset inventory spreadsheets listing operating system versions.

Answer

HR onboarding records showing background checks for all employees with physical access to the building.

Question 6

During an internal network security audit, an auditor needs to verify that administrative accounts are not sharing credentials. Which compliance artifact should the auditor inspect to validate individual accountability?

Accepted Answer

Active Directory Account Access Logs and Group Memberships. To verify that administrative accounts are not sharing credentials and to validate individual accountability, the auditor must inspect Active Directory account access logs and group memberships. These artifacts show which accounts exist, who is a member of privileged groups, and when each account was used to log on. If multiple administrators are using the same account, the logon events will show the same account name from different workstations or at overlapping times, which is the evidence of shared credentials.

Answer

BGP Routing Table Summaries

Answer

Network Switch Port VLAN Assignments

Answer

DNS Zone File Configurations

Question 7

An administrator needs to configure a Linux firewall using UFW (Uncomplicated Firewall) to allow incoming SSH traffic from a specific subnet (192.168.100.0/24). Which command should be executed?

Accepted Answer

ufw allow from 192.168.100.0/24 to any port 22 proto tcp. The correct UFW syntax to allow SSH from a specific subnet is `ufw allow from 192.168.100.0/24 to any port 22 proto tcp`. This rule specifies the source subnet, the destination (any), the port (22), and the protocol (TCP), which is exactly what UFW expects for a scoped allow rule.

Answer

ufw enable 192.168.100.0/24

Answer

ufw deny ssh

Answer

ufw route allow 22

Question 8

Which TWO methods are commonly used by Intrusion Detection and Prevention Systems (IDPS) to identify malicious network traffic? (Choose TWO)

Accepted Answer

Signature-based detection (matching known attack patterns and byte sequences). Signature-based detection is a core IDPS methodology: the sensor compares packet payloads and headers against a database of known attack patterns, byte sequences, and Snort/Suricata-style rules, generating an alert when a match occurs. Option E is also correct because anomaly-based detection builds a statistical or behavioral baseline of normal traffic (protocols, ports, bandwidth, connection rates) and flags deviations from that baseline as potential intrusions, which allows it to catch novel or previously unseen attacks. The remaining options are not IDPS detection methods: A describes illicit exploit acquisition, not traffic inspection; B is a nonsensical signal-conversion idea unrelated to packet analysis; and D is a manual network-availability action, not a detection technique.

Answer

Automatically purchasing new zero-day exploits from underground forums

Answer

Converting all network packets into analog audio signals for manual listening

Answer

Manually shutting down all enterprise internet circuits during off-peak hours

Question 9

A security engineer discovers that an attacker is exploiting a vulnerability in a web application's JSON Web Token (JWT) implementation by modifying the algorithm header to 'none' and bypassing signature verification. How should the application's JWT validation code be updated to fix this vulnerability?

Accepted Answer

Explicitly enforce a whitelist of approved cryptographic signing algorithms (e.g., RS256) and explicitly reject the 'none' algorithm in the JWT validation function.. The vulnerability arises because the JWT validation code trusts the 'alg' header from the token without verifying it against a list of allowed algorithms. An attacker can set 'alg' to 'none' and remove the signature, and if the code accepts it, signature verification is bypassed. The fix is to explicitly whitelist approved algorithms (e.g., RS256) and reject 'none' in the validation function, ensuring the token is signed with an expected algorithm. This prevents algorithm confusion attacks and enforces cryptographic integrity.

Answer

Upgrade the JWT token expiration time (exp claim) to expire within five minutes of creation.

Answer

Implement JSON Web Encryption (JWE) to payload data without verifying headers.

Answer

Store JWT tokens in HTTP-only, Secure cookies instead of local browser storage.

Question 10

A security administrator is configuring Azure Network Security Groups (NSGs) to protect a multi-tier application. Which rule evaluation principle does Azure apply when processing network traffic through an NSG?

Accepted Answer

First match based on rule priority number in ascending order. Azure NSGs evaluate rules in ascending order of priority number (100–4096), and the first rule whose source, destination, port, and protocol match the traffic is applied — no further rules are evaluated. This 'first match wins' model means a lower number equals higher precedence. If no rule matches, the default rules (AllowVnetInBound, AllowAzureLoadBalancerInBound, DenyAllInBound, etc.) apply.

Answer

Last match evaluated across all security rules

Answer

Explicit allow rules override all deny rules regardless of priority

Answer

Deny rules always take precedence regardless of priority number