Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A security analyst is reviewing the source code of a custom network service written in C. The service allocates a 256-byte buffer and uses the strcpy() function to copy incoming data into that buffer without verifying the length of the input. If an attacker sends a specially crafted payload that exceeds 256 bytes, which security control would be most effective at detecting and preventing the resulting exploitation at runtime?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Stack canaries
Correct. Stack canaries are placed before the return address on the stack. If a buffer overflow overwrites the canary, the program terminates, preventing control-flow hijacking. This is a highly effective runtime defense against stack-based buffer overflows.
B
Distractor review
Transport Layer Security (TLS)
Incorrect. TLS encrypts network traffic but does not protect against vulnerabilities in the application code itself, such as buffer overflows. It cannot prevent the exploitation of memory corruption bugs.
C
Distractor review
Code signing
Incorrect. Code signing verifies that the software has not been tampered with and identifies the publisher. It does not provide runtime protection against memory corruption exploits in the running application.
D
Distractor review
Data Execution Prevention (DEP)
Incorrect. DEP makes memory regions non-executable, which can prevent direct execution of injected shellcode. However, sophisticated attackers can bypass DEP using return-oriented programming (ROP). Stack canaries are generally more effective for detecting the overflow itself, even when DEP is present.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A laptop is suspected of being used in a malware incident. It is still powered on and connected to Wi-Fi. What should the responder do before shutting it down?
Question 2
An employee reports a ransomware note on a file server. The server is still powered on, shares are still being accessed, and management wants service restored as quickly as possible. What should the incident response team do first?
Question 3
An employee reports a ransomware note on a finance laptop. The laptop is still powered on, connected to Wi-Fi, and the user says they were just working in a spreadsheet. Management wants the fastest safe response that also preserves evidence. What should the responder do first?
Question 4
You are handed a company laptop suspected in an insider theft case. Legal says the evidence may be needed in court. Which action best preserves admissibility?
Question 5
A developer wants to reduce the risk of SQL injection in a new customer search form. Which two changes are the best mitigations? Select two.
Question 6
A branch office uses a flat LAN, and a compromise on one user workstation could spread quickly to finance systems. Management wants finance workstations isolated from general users, but finance staff still need access to a central finance application and network printer. What is the best design change?
FAQ
Questions learners often ask
What does this SY0-701 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Stack canaries — The vulnerability is a classic buffer overflow that can overwrite the return address on the stack. Stack canaries are small values placed before the return address; if a buffer overflow occurs, the canary is corrupted, and the program terminates before control can be hijacked. This makes stack canaries the most direct runtime mitigation for stack-based buffer overflows. Transport Layer Security (TLS) encrypts data in transit but does not prevent buffer overflows in the application. Code signing ensures the integrity and authenticity of the binary but does not stop exploitation once the code runs. Data Execution Prevention (DEP) prevents execution of code in non-executable memory regions; however, attackers can bypass DEP using return-oriented programming (ROP), while a stack canary would still detect the overflow and abort.
What should I do if I get this SY0-701 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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