SIP Server Security Weaknesses and Unsolicited Calls
Callers speaking a foreign language are using company phone numbers to make unsolicited phone calls to a partner organization. A security analyst validates through phone system logs that the calls are occurring and the numbers are not being spoofed. Which of the following is the most likely explanation?
Community Votes
67% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The core concept tested is SIP trunking security; the common trap is assuming that because numbers are not spoofed, the threat must be external or accidental, ignoring internal misconfiguration.
This question examines the risks associated with insecure Session Initiation Protocol (SIP) servers, specifically how weak security settings allow unauthorized use of company phone numbers for unsolicited calls. It establishes that internal logs confirming non-spoofed numbers point to a configuration vulnerability rather than external spoofing or provider errors.
Option D is the most common wrong answer because candidates confuse duplicate number assignment by providers with active call origination, failing to recognize that provider errors do not explain *who* is making the calls or why they appear as valid internal numbers in logs.
Community Discussion (6 comments)
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Expert Analysis
Why the Answer Is Correct
The correct answer is B because the logs confirm the numbers are not spoofed, meaning the calls originated from within the organization's own infrastructure. If the SIP server has weak security settings (e.g., lack of authentication, open ports, or default credentials), attackers or malicious insiders can exploit these vulnerabilities to place outbound calls using the company’s legitimate identity. This results in unsolicited calls that appear authentic because they use real, non-spoofed company numbers.Why the Other Options Are Wrong
Option A is unlikely because executives traveling internationally would typically have a reason for calling partners, but "unsolicited" implies an unwanted or malicious nature, not just cost avoidance. Option C is plausible but less specific than B; while disgruntled employees could make such calls, the question highlights a security analyst validating logs, pointing toward a systemic technical vulnerability (weak SIP settings) rather than a specific human motive. Option D is incorrect because if the service provider assigned duplicate numbers, the receiving end might see confusion, but it doesn't explain how foreign language speakers are actively placing calls through the company's system without authorization.Community Comment Notes
Community members generally agree on B, noting that weak SIP security allows unauthorized callers to use company numbers. One commenter emphasized that internal logs would not reveal provider-assigned duplicate numbers (D), reinforcing why B is the better technical explanation. Another user noted that checking SIP server security is the immediate next step for the analyst.Exam Strategy
When analyzing VoIP incidents, always distinguish between spoofed traffic (external forgery) and authorized-origin traffic (internal compromise). If logs show valid, non-spoofed numbers being used maliciously, look first for internal configuration weaknesses like open SIP trunks or missing authentication mechanisms.
Frequently Asked Questions
Why isn't D the answer if numbers are duplicated?
Provider duplication doesn't explain who is placing the calls. Weak SIP settings (B) provide the mechanism for unauthorized usage.
How do we know it's not disgruntled employees?
While possible, B is the broader technical cause. Weak settings enable both insider and outsider abuse, making it the primary security finding.