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# Anything limited by a number of attempts Race conditions are **vulnerabilities** that **appear** in webs that **limit the number of times you can perform an action**. A very easy example can be found in [**this report**](https://medium.com/@pravinponnusamy/race-condition-vulnerability-found-in-bug-bounty-program-573260454c43). # Using several times a one-time use code When you make the web page perform some **action** that **should be done only once**, but if the action is done **several times** you will be **benefited**, you really need to try a **Race condicion**.\ Most of the time this is directly related with **money** (if an action is made you get X money, so let's try to make it several time very quickly)**.** ## **Using from the same account the same code several times** For example, in [**this bug** ](https://hackerone.com/reports/759247)the hunter was able to **load the money inside a gift card several times.** This is the **turbo intruder** script used to **test** the **race condition** of the mentioned writeup: ```python def queueRequests(target, wordlists): engine = RequestEngine(endpoint=target.endpoint, concurrentConnections=30, requestsPerConnection=30, pipeline=False ) for i in range(30): engine.queue(target.req, i) engine.queue(target.req, target.baseInput, gate='race1') engine.start(timeout=5) engine.openGate('race1') engine.complete(timeout=60) def handleResponse(req, interesting): table.add(req) ``` Using also BURP you could also send the **request** to **Intruder**, set the **number of threads** to **30** inside the **Options menu and,** select as payload **Null payloads** and generate **30.** ## **Using the same code from different accounts** **If the previously proposal didn't work (try to use the same code several times from the same account) you try a variant:Try t use the same code from different accounts:** ```python def queueRequests(target, wordlists): engine = RequestEngine(endpoint=target.endpoint, concurrentConnections=5, requestsPerConnection=1, pipeline=False ) a = ['Session=','Session=','Session='] for i in range(len(a)): engine.queue(target.req,a[i], gate='race1') # open TCP connections and send partial requests engine.start(timeout=10) engine.openGate('race1') engine.complete(timeout=60) def handleResponse(req, interesting): table.add(req) ``` ## OAuth2 eternal persistence There are several [**OAUth providers**](https://en.wikipedia.org/wiki/List\_of\_OAuth\_providers). Theses services will allow you to create an application and authenticate users that the provider has registered. In order to do so, the **client** will need to **permit your application** to access some of their data inside of the **OAUth provider**.\ So, until here just a common login with google/linkdin/github... where you aer prompted with a page saying: "_Application \ wants to access you information, do you want to allow it?_" ### Race Condition in `authorization_code` The **problem** appears when you **accept it** and automatically sends a **`authorization_code`** to the malicious application. Then, this **application abuses a Race Condition in the OAUth service provider to generate more that one AT/RT** (_Authentication Token/Refresh Token_) from the **`authorization_code`** for your account. Basically, it will abuse the fact that you have accept the application to access your data to **create several accounts**. Then, if you **stop allowing the application to access your data one pair of AT/RT will be deleted, but the other ones will still be valid**. ### Race Condition in `Refresh Token` Once you have **obtained a valid RT** you could try to **abuse it to generate several AT/RT** and **even if the user cancels the permissions** for the malicious application to access his data, **several RTs will still be valid.** # References * [https://hackerone.com/reports/759247](https://hackerone.com/reports/759247) * [https://pandaonair.com/2020/06/11/race-conditions-exploring-the-possibilities.html](https://pandaonair.com/2020/06/11/race-conditions-exploring-the-possibilities.html) * [https://hackerone.com/reports/55140](https://hackerone.com/reports/55140)
Support HackTricks and get benefits! Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)! Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family) Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com) **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.** **Share your hacking tricks submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**