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GIAC

GSEC · Question #115

Which of the following is NOT typically used to mitigate the war dialing threat?

The correct answer is B. Setting modems to auto-answer mode. Setting modems to auto-answer mode is not a war dialing mitigation - it actively enables the attack by automatically accepting incoming calls from any dialer.

Network Security

Question

Which of the following is NOT typically used to mitigate the war dialing threat?

Options

  • ASetting up monitored modems on special phone numbers
  • BSetting modems to auto-answer mode
  • CProactively scanning your own phone numbers
  • DMonitoring call logs at the switch

How the community answered

(20 responses)
  • A
    5% (1)
  • B
    75% (15)
  • C
    10% (2)
  • D
    10% (2)

Why each option

Setting modems to auto-answer mode is not a war dialing mitigation - it actively enables the attack by automatically accepting incoming calls from any dialer.

ASetting up monitored modems on special phone numbers

Deploying monitored modems on specific numbers functions as a honeypot that detects and tracks war dialing activity, making it a valid defensive technique.

BSetting modems to auto-answer modeCorrect

Auto-answer mode causes a modem to pick up and respond to every incoming call without human intervention, which is precisely the condition war dialers exploit to find live modem connections. Enabling this setting increases the attack surface rather than reducing it, making it the opposite of a defensive control against war dialing.

CProactively scanning your own phone numbers

Proactively scanning your own phone number ranges - sometimes called defensive war dialing - lets you discover unauthorized modems before attackers do, which is a recognized mitigation.

DMonitoring call logs at the switch

Monitoring call logs at the telephone switch can reveal the sequential dialing patterns characteristic of war dialing attacks, making it a useful detection control.

Concept tested: War dialing attack mitigation techniques

Topics

#war dialing#modem security#dial-up attack#countermeasures

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