The word "modelling" is a gerund here.
The first sentence of the paragraph containing the sentence in question says: "The lawyer Susan W. Brenner proposed a second model for attribution..."

Now let's look at what "attribution could mean according to a sentence in the same book:
[Attribution] involves using technology to identify the attacker through hints, such as signatures...
This is why I used تشخیص/نعیین عامل, and by عامل, I actually mean عامل حمله.
Another option could be انتساب حمله, which is closer to the source, though I prefer the other one.