Cisco Cisco Email Security Appliance C160 Mode D'Emploi
Chapter 11 Data Loss Prevention
11-24
Cisco IronPort AsyncOS 7.5 for Email Configuration Guide
OL-25136-01
To calculate the risk factor, the classifier multiplies the number of matches for a
detection rule by the weight of the rule. If this value exceeds the detection rule’s
maximum score, the classifier uses the maximum score value. If the classifier has
more than one detection rule, it adds the scores for all of its detection rules into a
single value. The classifier maps the detection rules score (10 - 10000) on a scale
of 10 -100 using the logarithmic scale shown in
detection rule by the weight of the rule. If this value exceeds the detection rule’s
maximum score, the classifier uses the maximum score value. If the classifier has
more than one detection rule, it adds the scores for all of its detection rules into a
single value. The classifier maps the detection rules score (10 - 10000) on a scale
of 10 -100 using the logarithmic scale shown in
to create the risk
factor.
Classifier Examples
The following examples show how classifiers match message content.
Credit Card Number
Several DLP policy templates include the Credit Card Number classifier. The
credit card number itself is subject to various constraints, such as the pattern of
digits and punctuation, the issuer-specific prefix, and the final check digit. The
classifier requires additional supporting information to make a match, such as a
second credit card number, an expiration date, or the name of the card issuer. This
reduces the number of false positives.
credit card number itself is subject to various constraints, such as the pattern of
digits and punctuation, the issuer-specific prefix, and the final check digit. The
classifier requires additional supporting information to make a match, such as a
second credit card number, an expiration date, or the name of the card issuer. This
reduces the number of false positives.
Table 11-1
Logarithmic Scale for Calculating the Risk Factor
Rule Scores
Risk Factor
10
10
20
20
30
30
50
40
100
50
150
60
300
70
500
80
1000
90
10000
100