Validating input in java
There are four strategies for validating data, and they should be used in this order: This strategy is also known as "whitelist" or "positive" validation.The idea is that you should check that the data is one of a set of tightly constrained known good values. Data should be: This strategy, also known as "negative" or "blacklist" validation is a weak alternative to positive validation.Unless the business will allow updating "bad" regexes on a daily basis and support someone to research new attacks regularly, this approach will be obviated before long.Rather than accept or reject input, another option is to change the user input into an acceptable format Any characters which are not part of an approved list can be removed, encoded or replaced.Integrity checks must be included wherever data passes from a trusted to a less trusted boundary, such as from the application to the user's browser in a hidden field, or to a third party payment gateway, such as a transaction ID used internally upon return.The type of integrity control (checksum, HMAC, encryption, digital signature) should be directly related to the risk of the data transiting the trust boundary. However, validation should be performed as per the function of the server executing the code.It can take upwards of 90 regular expressions (see the CSS Cheat Sheet in the Development Guide 2.0) to eliminate known malicious software, and each regex needs to be run over every field. Just rejecting "current known bad" (which is at the time of writing hundreds of strings and literally millions of combinations) is insufficient if the input is a string.This strategy is directly akin to anti-virus pattern updates.
Use the global default policy to signal logical violations in your code or optionally specify your own handling. This library is available at Maven Central Repository.
Some documentation and references interchangeably use the various meanings, which is very confusing to all concerned.
This confusion directly causes continuing financial loss to the organization.
The account select option is read directly and provided in a message back to the backend system without validating the account number if one of the accounts provided by the backend system.
An attacker can change the HTML in any way they choose: rather than account names.