A. Untrained staff or ignorant computer users who inadvertently become the weakest link in your security chain
B. "zero-day" exploits are the weakest link in the security chain since the IDS will not be able to detect these attacks
C. "Polymorphic viruses" are the weakest link in the security chain since the Anti-Virus scanners will not be able to detect these attacks
D. Continuous Spam e-mails cannot be blocked by your security system since spammers use different techniques to bypass the filters in your gateway
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