PEN-200 Practice Test 5 — 10 Questions

Question 1

Why might a public exploit for a specific service fail to execute even when the service version matches the vulnerability description exactly?

Accepted Answer

The target environment has different memory protections or patch levels.. Public exploits are typically written against a specific environment, which may differ from your target's configuration. Variations in operating systems, patch levels, installed libraries, or memory protection mechanisms like ASLR and DEP can prevent the exploit from succeeding. Understanding these environmental dependencies is key to troubleshooting failed exploits, as it often requires you to manually port or adjust the exploit to fit the target's unique security posture.

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The exploit code is always written in an incompatible shell format.

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Public exploits are intentionally corrupted to prevent usage.

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You forgot to increase the network timeout settings.

Question 2

You have identified an open port 445 on a Windows machine. Which tool is most effective for checking if the machine is vulnerable to common SMB-based exploits like EternalBlue?

Accepted Answer

Use Nmap with the --script smb-vuln-ms17-010 argument.. Nmap's scripting engine (NSE) is the most effective way to check for specific vulnerabilities like EternalBlue without requiring a full-scale vulnerability scanner. The 'smb-vuln-ms17-010' script is specifically designed to detect this vulnerability. Using such targeted scripts allows for accurate assessment with minimal footprint, which is a hallmark of professional penetration testing practices, ensuring the system's security posture is evaluated safely and effectively during the reconnaissance phase.

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Use ping to verify the host is reachable.

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Run a full Nessus scan against the IP.

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Use telnet to manually send an exploit string.

Question 3

You need to fingerprint the web server technology behind an HTTP service without sending malformed or intrusive requests. Which two actions best accomplish passive-leaning banner and behavior fingerprinting during enumeration? (Choose two.)

Accepted Answer

Inspect the Server and X-Powered-By response headers returned in the HTTP reply.. Header inspection and error-page analysis both identify server technology using ordinary, non-destructive requests. Headers may name the server and runtime directly, while distinctive 404 templates expose the stack when banners are hidden. Together they fingerprint the web service safely, whereas crash attempts, full port sweeps, and credential guessing are intrusive or simply unrelated to identifying the technology.

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Send a buffer of several thousand bytes in the request line to provoke a crash signature.

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Run a full TCP port scan of all 65535 ports on the host to infer the web stack.

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Attempt default administrative credentials against the web login form.

Question 4

You have a Windows host with outbound internet access but want to avoid installing a full agent. You decide to use Chisel to pivot. Which statement accurately describes how Chisel establishes the tunnel in this scenario?

Accepted Answer

The Chisel client on the compromised host connects outbound to the Chisel server on your attacking machine, and the server can expose a SOCKS proxy on your side.. Chisel's client dials the server, so a compromised host with only outbound access can still establish a tunnel. When the server is started with reverse tunneling and SOCKS support, the operator gets a SOCKS proxy locally that routes through the client into the internal network. This makes Chisel a practical choice when a full agent is undesirable.

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Chisel encrypts traffic only when the --tls flag is used, and otherwise sends plaintext over the wire.

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The Chisel server must run on the compromised host so the client on your attacking machine can pull traffic from the internal network.

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Chisel requires a kernel TUN interface on both endpoints to carry the tunneled traffic.

Question 5

Why must you carefully identify 'bad characters' before finalizing an exploit payload?

Accepted Answer

To ensure the shellcode is correctly copied into memory in its entirety.. Bad characters are bytes that cause a function or protocol to stop processing input prematurely. If these characters exist in your shellcode, the application will truncate the payload. Identifying these characters ensures that the full exploit string is correctly placed into memory, allowing the overflow to reach the return address and execute the shellcode as intended without corruption or partial injection.

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To prevent the shellcode from triggering an antivirus alert.

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To allow the CPU to perform faster instruction decoding.

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To bypass DEP (Data Execution Prevention) controls.

Question 6

You are performing a penetration test against a Linux server and have obtained a copy of the /etc/shadow file. The file contains a hash for user 'admin' that starts with '$6$'. You want to crack this hash offline. Which hashcat mode should you use?

Accepted Answer

Mode 1800 (sha512crypt). The '$6$' prefix in /etc/shadow denotes SHA-512 crypt, which is handled by hashcat mode 1800 (sha512crypt). The other modes correspond to different algorithms: mode 500 for md5crypt ('$1$'), mode 3200 for bcrypt ('$2a$'), and mode 7400 for sha256crypt ('$5$'). Using the correct mode is essential for successful cracking. Therefore, mode 1800 is the right choice.

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Mode 7400 (sha256crypt)

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Mode 3200 (bcrypt)

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Mode 500 (md5crypt)

Question 7

You are testing a web application that sets a session cookie with the HttpOnly flag. You find a reflected XSS vulnerability on a page that does not require authentication. What is the primary impact of exploiting this XSS given the HttpOnly flag?

Accepted Answer

You can execute arbitrary JavaScript in the victim’s browser to perform actions as the victim, but you cannot directly read the session cookie via document.cookie.. HttpOnly is designed to prevent client-side scripts from reading cookie values, but it does not prevent script execution or stop the browser from sending the cookie with requests. An attacker who achieves XSS can still act as the victim by issuing requests, reading page content, or capturing keystrokes. The session cookie may be inaccessible to document.cookie, but the authenticated session remains exploitable.

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You can read the session cookie using document.cookie because HttpOnly only applies to cookies set over HTTPS.

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You can bypass HttpOnly by using XMLHttpRequest to fetch the cookie from the server’s response headers.

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You cannot execute JavaScript at all because HttpOnly blocks all script execution on the page.

Question 8

Which of the following best describes the function of the EIP register in the context of a stack-based buffer overflow?

Accepted Answer

It points to the memory address of the next instruction to be executed.. The EIP (Extended Instruction Pointer) register holds the memory address of the next instruction the CPU should execute. In an exploit, the goal is to overwrite this register by corrupting the saved return address on the stack. When the function finishes, the CPU pops this controlled value into EIP, forcing the processor to jump to the attacker's shellcode, thus hijacking the control flow of the entire application.

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It stores the current stack frame's base address.

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It keeps track of the number of active threads.

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It holds the results of arithmetic operations.

Question 9

Refer to the exhibit. If you attempt an SSH remote port forward (-R) to bind a port to all network interfaces on the server, what will happen?

Accepted Answer

The port will be bound to 127.0.0.1 instead of 0.0.0.0.. The 'GatewayPorts no' setting in the sshd_config specifically prevents forwarded ports from binding to any interface other than the loopback (localhost). Even if the user specifies 0.0.0.0 or a public IP in their SSH command, the server will ignore this request and bind the port only to 127.0.0.1. This is a common security hardening measure to prevent unauthorized access to forwarded ports from external networks.

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The request will be rejected and the connection will close.

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The server will allow the binding because it is a superuser request.

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The connection will hang indefinitely.

Question 10

During an authorized web application assessment, you discover a search page that reflects the query parameter directly into the HTML response body without encoding. You want to confirm the presence of a reflected cross-site scripting vulnerability using a minimal, non-destructive payload. Which of the following payloads is most likely to execute JavaScript in a victim's browser when injected into the vulnerable parameter?

Accepted Answer

. Reflected cross-site scripting occurs when user input is immediately returned by the web server without proper output encoding, allowing an attacker to inject client-side script. A script tag containing a simple alert is a reliable proof of concept because it executes in the victim's browser context when the crafted URL is visited. The other payloads target SQL injection or path traversal and do not demonstrate JavaScript execution.

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1' OR '1'='1

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../../../../etc/passwd

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'; DROP TABLE users; --