Bots against payment flows.
WHAT THEY ATTEMPT
Card testing with stolen numbers Credential stuffing against accounts Enumeration of account numbers or references Abuse of promotional credit Scraping of balances or data
WHAT CARD TESTING LOOKS LIKE
High volume, low value, high failure rate, from varied sources.
WHY IT MUST BE STOPPED QUICKLY
Fees accrue, decline ratios rise, and schemes intervene.
WHAT DETECTION SIGNALS EXIST
Velocity per address, device and account Failure rate far above normal Requests lacking normal browser characteristics Patterns in timing that are too regular
WHAT RESPONSES EXIST
Rate limiting Challenges Blocking sources Requiring authentication earlier
WHAT TO BE CAREFUL WITH
Blocking shared addresses, which affects many legitimate users.
WHY THAT MATTERS HERE
Address sharing is common, so address-based blocking has wide effect.
WHAT TO PREFER
Device and behavioural signals over address alone.
WHAT ENUMERATION PREVENTION REQUIRES
Identifiers that cannot be guessed Rate limiting on lookups Responses that do not reveal existence
WHAT TO MONITOR
Failure rates by endpoint, which reveal attacks in progress.
WHAT TO PREPARE
A rapid response, since these attacks develop in minutes.
