Cross-Origin Resource Sharing (CORS) | Complete Guide

In this video, we cover the theory behind Cross-Origin Resource Sharing (CORS) vulnerabilities, how to find these types of vulnerabilities from both a white box and black box perspective, how to exploit them and how to prevent them.
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▬ 📖 Contents of this video 📖 ▬▬▬▬▬▬▬▬▬▬
00:00 - Introduction
00:31 - Web Security Academy Course (bit.ly/30LWAtE)
01:42 - Agenda
02:30 - What is a CORS vulnerability?
33:35 - How to find CORS vulnerabilities?
42:37 - How to exploit CORS vulnerabilities?
50:25 - How to prevent CORS vulnerabilities?
51:47 - Resources
52:00 - Thank You
▬ 🔗 Links 🔗 ▬▬▬▬▬▬▬▬▬▬
Video slides: github.com/rkhal101/Web-Secur...
Web Security Academy: portswigger.net/web-security/...
Rana's Twitter account: / rana__khalil
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[@RanaKhalil101]

Don't want to wait for the weekly release schedule to gain access to all the videos and want to be added to a discord server where you can ask questions? Make sure to sign up to my course: bit.ly/30LWAtE ✨✨

[@Shintowel]

Love u

[@akr2dev]

Is your course available as one time purchase? Or I have to renew each month to keep access

[@RanaKhalil101]

@@akr2dev One time purchase

[@akr2dev]

@@RanaKhalil101 I was looking for a course that covers CORS. I think I am so lucky to find your course It will take me to a whole another level :) Thank you ~

[@klliiyougg6666]

Why you speak englih why

[@CookingCooking77]

You explain in the exact way a beginner would liked to be explained !

[@rohanadhvaryu]

This is the best ever explaination I have seen on an internet for the CORS topic, what an explaination!! Each and every details are covered here to understand it deeply and properly in a very easy language. I really appreciate. Thank you and and please keep it up. 🙂❤🙌

[@rahulaga]

totally agree on clarity of explanation !!

[@VladislavSnegurov]

I had so many confusion with Same-Origin-Policy and CORS, you made it clear for me once and forever. The most brilliant part of your lecture is that you provide real step-by-step case of attacking and exploiting vulnerability. Most explanations in Internet are just few general statements that produce more questions than answers. Thank you!

[@faique2995]

You are among the best teacher I have ever met in my life ♥️

[@Thomas_Grusz]

This is the best explanation of CORS and SOP I have come accross so far. Thank you!

[@mr.agoristgoldstein9109]

Signed up for Academy! Man what a deal….I am very grateful for your content. Thank you 🙏🏻

[@bhaskarvaka3931]

Wow ! The best video on CORS. This helps me to work on the solution for the issue identified in my application. Thank you so much!

[@hebafarahat]

I love how you always simplify things. You are amazing! keep it up Rana 🔥💪

[@squarebyte9846]

Great video! This makes CORS so easy to understand :D

[@danmcgirr4210]

You are amazing! Thanks for sharing so much knowledge. I've just found your academy through your Twitter. I'm looking forward to joining and training under your guidance. All the best!

[@0x_Eslam]

Love u sis❤ i hope u will be in jannah inshallah❤❤

[@jmukarram]

Very informative video. Thanks for sharing your knowledge and skill.

[@kutra100]

Excellent. Made it easy to understand and grasp. Thank you !

[@pascalerb5572]

Real good video! Thanks for this awesome work!

[@211986abhi]

Wow 👌 beautifully explained. Your work is amazing. Totally impressed.

[@TomAinsworth94]

Thanks a lot for the video Rana, it’s super helpful!

[@vicmann87]

This video has the best explanation that I've ever seen about this topic

[@korean6525]

Wonderful explanation!

[@dor1313]

Wow ! such a great explanation ! like & subscribed!

[@ankurarora1606]

Love your way of teaching

[@MereAYT]

This is really good and I am saving it ot watch a few times until it all clicks. Thanks!

[@abdallahazme4757]

For a full stack developer like me this was super super useful, SO MANY THANKS.

[@sp1460]

Your teaching skills are great. Thanks. Hope you make more videos on various topics.

[@jc_alpha]

Perfect explanation. Thank you!

[@vishalsharma-nx2fq]

Excellent video what a detailed explanation... Kudos to you

[@marclemessy2063]

thank you very much for your explanation, you were very clear. Keep it up

[@youssef_emad19]

You are my role model in this field

[@RafaelFoschiani]

Come here because i was having some issues with AWS Cloudfront/S3 CORS configuration, and find out a lot of vulnerabilties in the existing confgs LMAO. Thank you so much!

[@gauravkelkar4273]

Amazing explanation!!

[@user-lq3xl5xd5j]

This is the best explanation of CORS and SOP I Thank you, even your language it's easy to consider again thank you

[@ChillTamizha]

Nice video thanks for the resources that were shared in this video 👏

[@jogadornumerozero3257]

This channel is awesome, thank u soo much

[@cheolwang4389]

great job. love it!

[@mahalingappabirajdar5285]

Great Explanation!!!!!!!

[@shaifsec]

This is awesome contenet about CORS.

[@titanicsinclair1577]

finally new series is back after some time!

[@Ayushnigam806]

You Just Nailed it , Ma'am

[@timecop1983Two]

You are the best web HACKER I know!!! Keep up you're amazing content. I could not find Cross-Origin Resource Sharing on youtube but then I remeber you were in a david bombal show. So, keep it up... 👍👌✌

[@acronproject]

Thanks Ms.Khalil

[@jzbainabsbsosmsidnidnsi2647]

Thanks Rhana. You are the best🎉

[@burhanshah5855]

Absolutely fantastic Rana

[@JuanBotes]

thanks for making great content \o/

[@petebarnard123]

Brilliant explanation. thanks

[@mrkewi1]

you're awesome. please don't stop

[@ram-gb4xg]

Amazing!

[@JorgeRivera-rp1zw]

Hi, Dear Rana . Many thanks to share your video with us..? Succeds..!

[@sabuein]

Thank you.

[@tomkatrio182]

so helpful thanks

[@sksalman6359]

Thanks Rana Khalil 🥰🥰

[@ArindamKashyap-qk1ps]

Thanks a lot Rana. All my confusion are gone now. Thank you very much. Could you please make a video on Road to CEH Master, I'm thinking of taking the Elite package from EC council. I know you have cleared the OSCP and saw you video on David Bombal's channel. I got to know your videos from Portswigger's community solution. [ optional: you could make for the CEH Master one by collaborating with someone also].

[@QuranKareem22]

thansk❤

[@swamimzaman7058]

Please make the other videos available 🙏

[@microsoft14.]

God bless you 🙏

[@kokn3t]

Is it possible to exploit in "Authorization Bearer" JWT base web applications?

[@leonardofibonacci6574]

Good stuff here. What about JSONP for cross origin resource sharing? Is it a valid alternative to CORS? Are there security problems with JSONP?

[@klalafudaklalafu]

How it possible for script from another tab (21:25) to access bank's tab's cookies to make requests on bank site?

[@boobalandharani4848]

i need clarification . i changed the request header(CORS) origin url name( POST and GET method) and it get reflected in response. it will consider as defect or not .

[@jenks2897]

What if I don't what to access or change any data just want to click a button on website A which then clicks or simulate a click on website B and execute a function, does this falls under CORS ? If not any suggestion on how this can be done?

[@fathallahilyes529]

what mean access control allow origin header to null pls ?

[@AnujSharma-yv6gy]

at 36:44, it is said that if there aren't any CORS headers being used by the application, it can be due to the application making use of dynamic generation. Later at 37:33, we check if the value in the origin header is being reflected in ACAO CORS header. So basically we're finding flaws in dynamic generation by making use of what's being reflected in CORS' ACAO header. Aren't both these statements contradictory? If there are no CORS headers and the reason is dynamic generation then how can we test for dynamic generation using CORS headers?

[@AnujSharma-yv6gy]

@Elijah Rodgers but since it isn't CORS header, wasn't it there anyways? We need ACAO header in response to test which is one of the two CORS headers.

[@tiago7w_583]

Top

[@hatemabushaala2487]

👏

[@deepamsinha3933]

I have one doubt regarding this.Suppose domain A wants domain B to access its resources, so it whitelists it. Another domain C knows that B is whitelisted. Now, domain C sends a request and specifies Origin equal to domain B, so will it be able to access the resources on A? If yes, then is it so easy to spoof origin and just access resources on a different domain?

[@blackhatanonymous3687]

why other videos are hidden of csrf? This is due to schedule or will be hidden for all time?

[@ranjeetyaduvanshi6089]

can you make some videos that match with industry requirements sometimes I'm get stuck in doing stuff well I'm Network Security Analyst i wants to learn more something new to add in my skilll

[@jayak3768]

I love cats. As long as my bank account is safe.

[@saurabhjha8733]

Ninja Hattori

[@Ethical_Hacker216]

This vulnerability important ?! The issue you’ve described is related to Cross-Origin Resource Sharing (CORS) misconfiguration. CORS is a security feature implemented by web browsers to control which web domains can access resources on a given domain. In this case, the application has a CORS policy that allows access from any domain (Access-Control-Allow-Origin: *), which is considered overly permissive and poses a security risk.

[@katebanez7918]

I am the 404th like, but it's not found ;)

[@pauraspatil9314]

Nicely Explained !