Question 530
At a financial services branch, a test team is validating a change after this incident: A custom application signature matches every packet containing a generic four-byte string, producing false positives for unrelated business services. What evidence most directly verifies the intended outcome?
Explanation
Correct Answer
Representative approved application traffic matches while negative controls remain separately classified. This evidence directly tests the intended corrective action: Add appropriate context, protocol and offset/condition constraints to the custom signature. It confirms the failure mechanism—An overbroad signature can misidentify protocols that share common payload bytes.—has been addressed in the actual affected flow.
Incorrect Answers
The intended safe exploit simulation is handled while legitimate app sessions remain functional. This would verify resolution of a different case: A company imports a custom vulnerability signature without testing the affected application, and routine traffic is unexpectedly blocked. It does not show that the reported issue was fixed or that its intended action—Add appropriate context, protocol and offset/condition constraints to the custom signature.—worked.
The test URL matches the custom category and shows the expected permitted logging. This would verify resolution of a different case: A custom URL category is created for a sanctioned research service but the firewall still blocks its normal category because no URL Filtering profile references the new category. It does not show that the reported issue was fixed or that its intended action—Add appropriate context, protocol and offset/condition constraints to the custom signature.—worked.
A policy match test confirms the intended address is selected and unrelated subnets are excluded. This would verify resolution of a different case: A cloud administration team changes an address group's membership but mistakenly assumes that a nested group contains the new address automatically. It does not show that the reported issue was fixed or that its intended action—Add appropriate context, protocol and offset/condition constraints to the custom signature.—worked.