Communications can be processed with multiple countermeasures to identify attacks. Each countermeasure can compute a probability of a communication containing an attack and an accompanying confidence score indicating confidence in the probability. Combining the probabilities can produce a composite probability and associated confidence of the communication containing an attack. The composite probability and confidence scores can be produced from a weighted combination of the individual countermeasure probabilities and confidence scores. Weighting factors can be generated or obtained from a database that stores profiles of confirmed attacks.