CNSP Exam Dumps - The SecOps Group Security Practitioner Questions and Answers

SSH (Secure Shell), per RFC 4251, uses asymmetric cryptography (e.g., RSA, ECDSA) for secure authentication:

Key Pair:

Public Key:Freely shareable, used to encrypt or verify.

Private Key:Secret, used to decrypt or sign.

Process:

User generates a key pair (e.g., ssh-keygen -t rsa -b 4096).

Public Keyis uploaded to the server, appended to ~/.ssh/authorized_keys (e.g., via ssh-copy-id).

Private Key(e.g., ~/.ssh/id_rsa) stays on the user’s machine.

Authentication: Client signs a challenge with the private key; server verifies it with the public key.

Technical Details:

Protocol: SSH-2 (RFC 4253) uses a Diffie-Hellman key exchange, then public-key auth.

Files: authorized_keys (server, 0644 perms), private key (client, 0600 perms).

Security: Private key exposure compromises all systems trusting the public key.

Security Implications:CNSP likely stresses key management (e.g., passphrases, rotation) and server-side authorized_keys hardening (e.g., PermitRootLogin no).

Why other options are incorrect:

B:Uploading the private key reverses the model, breaking security—anyone with the server’s copy could authenticate as the user. Asymmetric crypto relies on the private key remaining secret.

Real-World Context:GitHub uses SSH public keys for repository access, with private keys on user devices.References:CNSP Official Documentation (SSH Security); RFC 4253 (SSH Authentication Protocol).

In Linux, file visibility is determined by naming conventions, impacting how files are listed or accessed in the file system.

Why D is correct:"Dotfiles" are files or directories with names starting with a dot (e.g., .bashrc), making them hidden by default in directory listings (e.g., ls requires -a to show them). They are commonly used for user configuration, as per CNSP’s Linux security overview.

Why other options are incorrect:

A:Library files (e.g., in /lib) aren’t inherently hidden.

B:Driver files (e.g., kernel modules in /lib/modules) aren’t dotfiles by convention.

C:System files may or may not be hidden; "dotfiles" specifically denotes hidden status.

References:CNSP "Linux File System Security" (Section on File Types) defines dotfiles as hidden configuration files.

Adding a user to a domain group like "Domain Admins" requires the correct command and scope (domain vs. local).

Why A is correct:net group "Domain Admins" John /add /domain adds user John to the domain-level "Domain Admins" group, per CNSP’s domain privilege management.

Why other options are incorrect:

B:net user creates users, not group memberships; syntax is wrong.

C:/admin is invalid; correct group specification is missing.

D:Targets local "Administrator" group, not domain "Domain Admins".

References:CNSP "Domain Administration" (Section on net Commands) validates net group with /domain.

DDoS (Distributed Denial of Service) attacks aim to overwhelm a target’s resources with excessive traffic, disrupting availability, whereas other attack types target different goals.

Why D is correct:Brute force attacks focus on guessing credentials (e.g., passwords) to gain unauthorized access, not on denying service. CNSP classifies it as an authentication attack, not a DDoS method.

Why other options are incorrect:

A:SYN Flood exhausts TCP connection resources, a classic DDoS attack.

B:NTP Amplification leverages amplified responses to flood targets, a DDoS technique.

C:UDP Flood overwhelms a system with UDP packets, another DDoS method.

References:CNSP "DDoS Attack Types" (Section on Attack Classification) excludes brute force from DDoS categories, listing SYN, NTP, and UDP floods as examples.

The EICAR test file is a standardized tool in security testing, designed for a specific purpose.

Why A is correct:The EICAR file (a 68-byte string) triggers antivirus detection without harm, testing response capabilities. CNSP recommends it for AV validation.

Why B is incorrect:It has no role in testing encryption; it’s solely for AV functionality.

References:CNSP "Antivirus Testing" (Section on EICAR) describes its use for AV response verification.

TLS (Transport Layer Security)secures communication (e.g., HTTPS) using certificates, per RFC 8446. A certificate includes:

Validity Period:Start and end dates (e.g., "Not After: March 8, 2025").

Purpose:Authenticates the server and encrypts the session.

Scenario:An expired TLS certificate (e.g., past "Not After" date). Modern browsers (e.g., Chrome, Firefox) validate certificates during the handshake:

ClientHello:Browser initiates TLS.

ServerHello:Server sends its certificate.

Validation:Browser checks expiration, CA trust, etc.

If expired, browsers reject the handshake, displaying errors (e.g., "NET::ERR_CERT_DATE_INVALID"). No session key is negotiated, andcommunication doesn’t proceed over TLS. Users may bypass warnings (e.g., "Advanced > Proceed"), but this is unencrypted or uses a fallback (not standard TLS), breaking security guarantees.

Security Implications:Expired certificates expose sites to MITM attacks, as trust is lost. CNSP likely emphasizes certificate management (e.g., automation with Let’s Encrypt) to avoid this.

Why other options are incorrect:

B. The communication is still over TLS:False; an expired certificate halts the TLS handshake in compliant browsers. Legacy systems might negotiate insecurely, but this isn’t "TLS" per standards.

Real-World Context:The 2019 Equifax breach partially stemmed from expired certificates missing vulnerabilities.References:CNSP Official Study Guide (TLS/SSL Security); RFC 8446 (TLS 1.3).

TCP (Transmission Control Protocol) ensures reliable, ordered data delivery via a connection-oriented handshake, contrasting with UDP’s lightweight, connectionless approach. Analyzing each service:

C. HTTP (Hypertext Transfer Protocol):Uses TCP (port 80) for web traffic. TCP’s reliability ensures HTML, images, etc., arrive intact. HTTPS (TCP 443) extends this with TLS. RFC 2616 mandates TCP.

A. SNMP (Simple Network Management Protocol):Defaults to UDP (port 161) for monitoring devices. UDP’s speed suits its lightweight queries, though TCP variants exist (rarely used).

B. NTP (Network Time Protocol):Uses UDP (port 123) per RFC 5905. UDP minimizes latency for time sync, tolerating occasional packet loss.

D. IKE (Internet Key Exchange):Part of IPsec, uses UDP (port 500) per RFC 7296. UDP suits its negotiation phase; TCP isn’t standard.

Security Implications:TCP services like HTTP are more prone to state-based attacks (e.g., SYN floods) than UDP counterparts. CNSP likely contrasts TCP vs. UDP in protocol analysis.

Why other options are incorrect:

A, B, D:All default to UDP for efficiency, not TCP’s reliability.

Real-World Context:Firewalls prioritize TCP 80/443 rules for HTTP/HTTPS, while UDP 123 is opened for NTP servers.References:CNSP Official Study Guide (Network Protocols); RFC 2616 (HTTP), RFC 1155 (SNMP).

In Linux/Unix, file permissions are displayed in a 10-character string (e.g., -rwxr-xr-x), where the first character is the file type (- for regular files) and the next nine are permissions for user (owner), group, and others (rwx = read, write, execute). Special bits likeSUID(Set User ID) modify execution behavior:

SUID:When set, a program runs with the owner’s permissions (e.g., root) rather than theexecutor’s. It’s denoted by an s in the user execute position (replacing x if executable, or capitalized S if not).

Analysis:

-rwxr-sr-x (myfile): User: rwx, Group: r-s (SGID), Others: r-x. The s is in the group execute position, indicating SGID, not SUID.

-rwsr-xr-x (myprogram): User: rws (SUID), Group: r-x, Others: r-x. The s in the user execute position confirms SUID; owned by root, it runs as root.

-rw-r--r-s (anotherfile): User: rw-, Group: r--, Others: r-s. The s is in the others execute position, but no x exists, making it irrelevant (and not SUID). Typically, s here would be a sticky bit on directories, not files.

Security Implications:SUID binaries (e.g., /usr/bin/passwd) are common targets for privilege escalation if misconfigured (e.g., writable by non-root users). CNSP likely emphasizes auditing SUID permissions with find / -perm -u=s.

Why other options are incorrect:

A. myfile:Has SGID (s in group), not SUID.

C. anotherfile:The s doesn’t indicate SUID; it’s a misapplied bit without execute permission.

D. All of the above:Only myprogram has SUID.

Real-World Context:Exploiting SUID binaries is a classic Linux attack vector (e.g., CVE-2016-1247 for Nginx).References:CNSP Official Study Guide (Linux Permissions); Linux File System Documentation.