Answer :
These sort of attacks are known are Injected IFrame Attacks. The Injected IFrame Attacks are a common Cross Site Scripting or XCC attack that contains multiple or single iFrame tags implemented within a page which is not visible to user. User unintentionally enters his information which is posted to hacker’s server and information’s gets hacked.
If you include all zeroes, then it should be 1,000,000,000. Otherwise it’s 999,999,999.
Think of how between 0-9 theres 10 numbers, and use that logic towards 000000000-999999999
