CTE Cybersecurity & Risk 3 — Questions and Answers
Question 1: A telecom operator's 5G core network uses APIs exposed via HTTP/2. Which OWASP category represents the highest risk for these interfaces?
- Broken Object Level Authorization (BOLA) (Correct answer)
- SQL Injection
- XML External Entity (XXE)
- Buffer Overflow
Correct answer: Broken Object Level Authorization (BOLA)
BOLA (formerly IDOR) is the top API security risk, where attackers access objects by manipulating resource identifiers in API calls.
Question 2: What is the primary security concern with deploying Network Function Virtualization (NFV) in a telecommunications environment?
- Increased latency in packet processing
- Hypervisor vulnerabilities can compromise multiple virtual network functions simultaneously (Correct answer)
- Difficulty in scaling virtual functions horizontally
- Higher power consumption compared to physical appliances
Correct answer: Hypervisor vulnerabilities can compromise multiple virtual network functions simultaneously
In NFV environments, a compromised hypervisor (VM escape) can expose all virtual network functions running on that physical host.
Question 3: A CTE executive is establishing a Business Continuity Plan for cybersecurity incidents. Which metric defines the maximum acceptable time to restore a critical telecom service after a breach?
- Recovery Point Objective (RPO)
- Recovery Time Objective (RTO) (Correct answer)
- Mean Time Between Failures (MTBF)
- Mean Time to Repair (MTTR)
Correct answer: Recovery Time Objective (RTO)
RTO defines the maximum acceptable duration of a service outage before it causes unacceptable business impact.
Question 4: Which type of cryptographic attack specifically targets the handshake process in TLS connections used to secure telecom management interfaces?
- Birthday attack
- BEAST (Browser Exploit Against SSL/TLS) (Correct answer)
- Rainbow table attack
- Pass-the-hash attack
Correct answer: BEAST (Browser Exploit Against SSL/TLS)
BEAST exploits a vulnerability in TLS 1.0's CBC mode cipher implementation during the handshake to decrypt encrypted data.
Question 5: An enterprise customer reports that calls originating from their PBX are being fraudulently redirected to international premium-rate numbers. This is best described as:
- Vishing
- Toll fraud / PBX hacking (Correct answer)
- War dialing
- Call spoofing
Correct answer: Toll fraud / PBX hacking
Toll fraud via PBX hacking involves unauthorized access to a PBX system to make calls to premium-rate or international numbers at the victim's expense.
Question 6: In a telecom risk register, what does 'residual risk' represent after security controls are applied?
- The original risk before any controls were implemented
- The risk that remains after existing controls are accounted for (Correct answer)
- The risk transferred to a third-party insurer
- The projected risk level five years in the future
Correct answer: The risk that remains after existing controls are accounted for
Residual risk is the remaining exposure after all implemented controls have reduced the inherent risk to an acceptable level.
Question 7: A telecom provider implements STIR/SHAKEN. What specific security problem does this framework address?
- Encrypting VoIP media streams end-to-end
- Authenticating caller ID to combat spoofed robocalls (Correct answer)
- Securing SIP registration against MITM attacks
- Preventing toll bypass fraud in interconnect agreements
Correct answer: Authenticating caller ID to combat spoofed robocalls
STIR/SHAKEN uses digital certificates to cryptographically attest the legitimacy of caller ID information, combating illegal caller ID spoofing.
CTE Cybersecurity & Risk 3
A telecom operator's 5G core network uses APIs exposed via HTTP/2.
Which OWASP category represents the highest risk for these interfaces?