#learn365 Day-12: Unicode Normalization
This attack is hard to explain w/o proper graphics. Please refer to the references mentioned for a detailed explanation. This is a really good attack vector to try and consider while doing PT/BB.
#bugbountytips #AppSec #infosec
Unicode to ASCII Transformation is a two-step process.

1. Normalization: Where the characters are converted to a standardized form
2. Punycoding: Where the Unicode is turned into ASCII

There are two overall types of equivalence between characters:......
1. Canonical Equivalence: Characters are assumed to have the same appearance and meaning when printed or displayed.

2. Compatibility Equivalence: This is a weaker equivalence, in that two values may represent the same abstract character but can be displayed differently.
# There are 4 Normalization AlgoDefined by Unicode Standard:

1. Normalization Form D (NFD): Canonical Decomposition
2. Normalization Form C (NFC): Canonical Decomposition, followed by Canonical Composition
3. Normalization Form KD (NFKD): Compatibility Decomposition
4. Normalization Form KC (NFKC): Compatibility Decomposition, followed by Canonical Composition

# Some Vulnerabilities that can be exploited using this abuse:
1. WAF & Filter Bypass for Attacks like XSS, SQLi, etc.
2. Account Takeovers
3. Text Transformation Attacks
4. Visual Spoofing Attacks
5. Advance Phishing Attacks
6. Host Split Vulnerability
7. Host Bond Vulnerability

# References
- docs.oracle.com/javase/tutoria…
- owasp.org/www-pdf-archiv…
- book.hacktricks.xyz/pentesting-web…
- engineering.atspotify.com/2013/06/18/cre… (Interesting one)

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More from @harshbothra_

13 Jan
#learn365 Day-13: WebSocket Vulns (Intro)

WebSocket is a network protocol that enables 2-way communication b/w client & server. In the HTTP standard, where the one-party has to wait for the req./res from another party before performing the next action.

The major goal of WebSocket is to enable real-time communication and can widely be seen in IM applications.

I will be diving the WebSocket learning into 3 parts and I will post more about various attacks in the next two days.

# Web socket Protocol Scheme

1. Websockets use wss:// and ws:// as the protocol scheme.
2. This is similar to HTTPS and HTTP. Here, the WSS:// is a secure channel where WS:// is an insecure channel.
Read 7 tweets
11 Jan
#Learn365 Day-11: Cache Poisoned Denial of Service (CPDos)
AIO Resource: cpdos.org
- One of a kind of Web Cache Poisoning attack that affects the resources used by an application to create a denial of service situation.

#bugbountytips #AppSec #infosec

# Working

The working of this attack is theoretically very simple to understand:

1. The attacker sends a request to the server containing a malicious header with a malicious value. This can be any random header.
ex: x-mal-example: tohackthehacker
2. This request is first processed by the intermediate cache server to check if the copy exists.
3. The cache server forwards the attacker's request with malicious headers to the origin server as it doesn't store a fresh copy of the requested resource.
Read 16 tweets
9 Jan
#Learn365 Day - 8: JSONP Attack
(Deleted prev. post and re-sharing as there are some modifications & to avoid false statement)
JSONP stands for JavaScript Object Notation with Padding which allows sending JSON data across domains without worrying about Cross-Domain Issues. (1/n)
It utilizes <script> tag to perform the action instead of using XHR. However, the function requires to be existing in the global scope.
It is an insecure communication method & should be used when no personal/sensitive data is involved & sanitizing the callback function.
(3/n)There are multiple attacks affecting the JSONP implementation as it doesn't have a security feature.
The “padding” or function to call with the JSON data, is often specified as a parameter. Often this parameter is called callback and is reflected as-is in the response.
Read 8 tweets
7 Jan
#learn365 Day-7: Cross-Site Script Inclusion (XSSI)
- XSS & XSSI are differemt.
In XSS, the payload is included on the victim to perform an action. However, In the case of XSSI, the victim's code (JS) is embedded in the attacker-controlled page.

#BugBountyTips #infosec (1/n)
In XSSI, the goal is to usually steal the data bypassing the restrictions such as the Same Origin Policy (SOP).
XSSI is less utilized and I never paid much attention to this attack vector. This seems to be an interesting and realistic, easy to exploit attack vector.
This attack is to mainly target the sensitive information that might get dynamically stored in the javascript files when a user performs some activity. If there are not proper restrictions set, an attacker can easily read and get hold of sensitive information.
Read 10 tweets
6 Jan
#Learn365 Day-6: Cross-Site Leaks

Goldmine to Learn: xsleaks.com

Cross-Site Leaks/XS-Leaks is a less explored security issue that usually comes from Side-Channel Attacks. I found this an interesting vector but unusual.


#BugBountyTips #infosec #AppSec
This basically utilizes the web's core principle of composability in order to determine & extract useful information.

XS-Leaks take advantage of small pieces of information that are exposed during interactions between websites.
Cross-Site Oracle.

This can be considered as a querying mechanism. The information used for this attack is of binary form and called Oracles. It usually has an answer of "Yes" or "No". You can say True or False.
Read 11 tweets
5 Jan
#Learn365 Day-5: Client-Side Template Injection (CSTI)
1. This occurs at the client-side like other JS attacks such as XSS.
2. This is mainly seen in the various JS libraries like AngularJS, VueJS etc which utilize the template engines at the client-side.
3. The presence of "ng-app" in the page source identifies the use of templates.
4. If the application directly accepts the input and process it without any validation, it may be vulnerable to CSTI.
5. CSTI leads to perform cross-site scripting attacks by escaping...
6. Testing this issue is similar to Server-Side Template Injection.
7. Steps:
a. In the suspected field, provide a payload like {{11*5}}
b. If the response reflected is 55, this tells that there is the use of the template and further you can try performing CSTI to XSS
Read 4 tweets

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