This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
CORS Explained and Common Misconfigurations tests a header you paste. A reflected origin, or a star with credentials, is a finding. Do not publish the header during the reading.
Write the system you administer, the name of this change, and the time. A second change waits until this line has been read back.
The browser tool drafts text or reads a paste you already hold. It does not log in, it does not scan a network you do not administer, and it does not apply.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. A sample password is replaced.
The change you can finish
Apply nothing while you are writing the note. When the lab window opens, it is one change on the system named in the ticket. Read the draft, then the system, then decide.
Rollback is the file, the record, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.
- Write the site you administer.
- Paste only a header you hold.
- Mark a reflected origin or a star with credentials.
- Do not publish a change.
- Stop.
Mistakes that outlive the statement
CORS Explained and Common Misconfigurations goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- An arbitrary origin reflected.
- A star origin combined with credentials.
- The header published during the reading.
Decisions to write down
One decision for CORS Explained and Common Misconfigurations: The site is yours. The finding is a finding. Nothing is published. Credentials stay off a star origin. And one header is enough.
Checks before you call it done
Confirm this before you call the change done: The site is written. The header was read. Nothing was published. The finding is one sentence. And a second person can say the origin. If one of those fails, stop.
# CORS reading. Do not publish.
# Do not reflect an arbitrary origin.
Before you leave the system
CORS Explained and Common Misconfigurations ends when the system in the note is the system in the ticket. If it is not, stop.
The draft stays a draft until a person has read the names in it. A generator does not log in, does not scan, and does not send mail.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you publish because a draft included them.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save. A sample password is replaced. It is not a password you keep.
One change is the window. If two things move and the result is wrong, you will not know which one did it.
If the same step fails twice, stop for the day. Restore the copy you took first.
A second person reads the scope aloud. If they cannot find it in the ticket, the note is not done.
This page is a planning guide. It is not legal advice, not an audit opinion, not a vendor manual, and not the text of a standard. You do not disable a security control to make a check pass. You do not use the page against a system you do not administer.
Tools for this guide
These tools run in the browser on this site. They do not log into your machines.
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The pillar for this page, and the next published pages filed with it.