High Security Question 207 of 226

How do you prevent CSRF?

MERN Full Stack · Speak this in 60–90 seconds · Faridabad & Delhi NCR

PICTURE THIS: A SENTENCE BECOMES TOKENS

The model does not read letters like humans. It reads these pieces, then predicts the next one.

Simple meaning

Browsers auto-send cookies, so a malicious site can trigger state-changing requests.

WHY — Security instead of guessing?

Why interviewers care about Security:

This is a process

question about Security.

Panels listen for order,

trade-offs, and what you would actually do on a Full Stack project - not buzzwords.

Stay structured

Name the idea, why it exists, then one short example.

Close cleanly

End with when you use it and one common pitfall.

STEPS — What happens with tokens?

Before the model can read a sentence, it goes through these steps:

1
Browsers auto-send cookies, so
a malicious site can trigger state-changing requests.
2
SameSite cookies, CSRF tokens,
and avoiding cookie auth for pure Bearer APIs help.
3
I treat cookie-based sessions
as CSRF-sensitive.
4
Context mix
Attention looks at nearby tokens together.
5
Next token
The model scores what should come next.
6
Decode
IDs turn back into readable text.

EXAMPLE — See it in action

Let's see how a real sentence is tokenized (tokens may vary by model):

Input text

“SameSite cookies, CSRF tokens, and avoiding cookie auth for pure Bearer APIs hel”

Tokenized output

SameSitecookiesCSRFtokensandavoiding

Token IDs (example)

2987408337471632900

Note: Actual tokens and IDs depend on the tokenizer (e.g., GPT, Llama, etc.).

Key takeaway

Browsers auto-send cookies, so a malicious site can trigger state-changing requests. SameSite cookies, CSRF tokens, and avoiding cookie auth for pure Bearer APIs help.