application security

Candidates who say 'everything is new' and candidates who say 'nothing is new' both lose this one. The answer that scores names exactly three differences and keeps the rest of the toolkit.

A reset flow is a second login page with weaker checks. Interviewers use it because every step has a classic bug, and the strong answer finds them in order.

The token tells you which algorithm to use and where to find the key. Believing it is how signature checks become no checks.

Three bugs, one cause. The answer that scores names the cause, explains why parameters are structural, and lands on why prompts have no parameters.

'Sanitise input' is the answer that fails. The interviewer wants encoding at the point of output, for the specific context, with CSP behind it.

A browsing tool is a URL fetcher whose destination is chosen by text anyone can write. The interviewer wants the defences in the tool and the network, not the prompt.

Reading files top to bottom finds style issues. A security review starts from sources, sinks and the checks between them, and AI code adds a new source.

The model is not the attacker, but whoever wrote the document it just read might be. Every argument in a tool call is untrusted input.

Scanners rarely find it, because every request looks valid. Finding it at scale is a testing design problem, not a scanning problem.

Three browser rules that candidates mix up constantly. The JWT follow-up exposes whether you know which one depends on cookies.

The format is the bug. JSON cannot call functions; pickle is designed to. The AI version is the model checkpoint you just downloaded.

File tools take paths from the model, and the model takes ideas from whatever it read. A string check for '..' is not confinement.

The model did not write malicious HTML on its own; a web page it summarised did. Then the conversation was shared, and the renderer trusted it.

Model a bounded reservation workflow, run an offline invariant fixture, and reason about retries, contention, immutable intent and uncertain external outcomes.

Every attribute answers one question: over which connections, to which scripts, from which sites and to which hosts does this cookie travel? Get those four right and most session theft paths close.

Logging in is one moment; a session lasts hours or months. Most session bugs live in what happens between: identifiers that never change, timeouts nobody enforces, and logouts that only clear the browser.

The user clicks a button on your page while believing they are on someone else's. The fix is a response header that tells the browser who may frame you, not script that tries to escape the frame.

No error messages does not mean no injection. And the sort column is the one place where 'just use parameters' does not work, so you need a different fix.

An ORM parameterises the queries it builds. It cannot protect the queries you build around it, or the data you trusted because it came from your own database.

No SQL does not mean no injection. When a query is a JSON object, the attack is sending an object where the code expected a string.

CORS never blocks a request from being sent. It decides whether another site's script may read the answer, and with credentials allowed, that answer contains the logged-in user's data.

Interviewers ask for the list to see whether you are current. They ask how you would use it to see whether you understand it is an awareness document, not a standard.

The login form is the front door, but attackers use the side doors: reused passwords, guessable recovery, and MFA that can be phished or reset by a support agent.

Every check passed and every write succeeded. The money still left twice, because the check and the write were two steps and another request got between them.

CSRF defences stop other sites from acting as the user. XSS is not another site: it is code running inside yours, with everything your own pages can do.

A WebSocket starts as an HTTP request that carries the user's cookies and skips CORS. The scored answer explains the hijack, then the controls that a long-lived connection needs that a normal request does not.

Uploads bring classic file-handling bugs into AI products. The scored answer covers the parsers, fetchers and storage around the model, not only what the model reads.