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*`"0xAAAA" == "43690" -> True` Strings composed by numbers in dec or hex format can be compare to other numbers/strings with True as result if the numbers were the same (numbers in a string are interpreted as numbers)
*`"0e12334" == "0" --> True` This is very interesting because in some cases yo can control the string input of "0" and some content that is being hashed and compared to it. Therefore, if you can provide a value that will create a hash starting with "0e" and without any letter, you could bypass the comparison. You can find **already hashed strings** with this format here: [https://github.com/spaze/hashes](https://github.com/spaze/hashes)
*`"X" == 0 --> True` Any letter in a string is equals to int 0
Con estas igualdades se pueden bypasear comparaciones de PHP (teniendo en cuenta que todo lo que se manda por parámetros normales de formulario siempre son strings).\
Sobre todo usando el truco de String que empieza por "0e" siempre es igual a "0", así si hay que pasar un hmac y podemos alterar valores, podemos enviar como hmac simplemente "0" y si el hmac sale que vale "0eXXXXXXXXXXX" pues dará correcto y se lo tragará\
Se puede intentar enviar los datos encodeados como json a ver si los lee (hay que cambiar la cabecera de tipo de datos para decir que es json y rezar para que se lo coma) (en json se elige el tipo de datos)
If this function is used for **any authentication check** (like checking the password) and the user controls one side of the comparison, he can send an empty array instead of a string as the value of the password (`https://example.com/login.php/?username=admin&password[]=`) and bypass this check:
Even if `===` is **being used** there could be errors that makes the **comparison vulnerable** to **type juggling**. For example, if the comparison is **converting the data to a different type of object before comparing**:
**`preg_match()`** could be used to **validate user input** (it **checks** if any **word/regex** from a **blacklist** is **present** on the **user input** and if it's not, the code can continue it's execution).
However, when delimiting the start of the regexp`preg_match()` **only checks the first line of the user input**, then if somehow you can **send** the input in **several lines**, you could be able to bypass this check. Example:
If you can send to `preg_match()` a valid very **large input**, it **won't be able to process it** and you will be able to **bypass** the check. For example, if it is blacklisting a JSON you could send:
* **register\_globals**: In **PHP < 4.1.1.1** or if misconfigured, **register\_globals** may be active (or their behavior is being mimicked). This implies that in global variables like $\_GET if they have a value e.g. $\_GET\["param"]="1234", you can access it via **$param. Therefore, by sending HTTP parameters you can overwrite variables** that are used within the code.
* The **PHPSESSION cookies of the same domain are stored in the same place**, therefore if within a domain **different cookies are used in different paths** you can make that a path **accesses the cookie of the path** setting the value of the other path cookie.\
This way if **both paths access a variable with the same name** you can make the **value of that variable in path1 apply to path2**. And then path2 will take as valid the variables of path1 (by giving the cookie the name that corresponds to it in path2).
* When you have the **usernames** of the users of the machine. Check the address: **/\~\<USERNAME>** to see if the php directories are activated.
* [**LFI and RCE using php wrappers**](../../../pentesting-web/file-inclusion/)
The supported algorithms are: `PASSWORD_DEFAULT` and `PASSWORD_BCRYPT` (starts with `$2y$`). Note that **PASSWORD\_DEFAULT is frequently the same as PASSWORD\_BCRYPT.** And currently, **PASSWORD\_BCRYPT** has a **size limitation in the input of 72bytes**. Therefore, when you try to hash something larger than 72bytes with this algorithm only the first 72B will be used:
If a **PHP page is printing errors and echoing back some input provided by the user**, the user can make the PHP server print back some **content long enough** so when it tries to **add the headers** into the response the server will throw and error.\
In the following scenario the **attacker made the server throw some big errors**, and as you can see in the screen when php tried to **modify the header information, it couldn't** (so for example the CSP header wasn't sent to the user):
Esta función dentro de php permite ejecutar código que está escrito en un string con el objetivo de que se devuelva true o false (y dependiendo de esto alterar la ejecución). Por lo general se introducirá la variable del usuario entre medias de un string. Por ejemplo: assert("strpos($\_GET\['page']),'..') === false") --> En este caso el payload para ejecutar un comando podría ser:
El caso es que hay que romper la query, ejecutar algo y volver a arreglarla (para ello nos servimos del "and" o "%26%26" o "|" --> el "or", "||" no funcionan pues si la primera es cierta deja de ejecutar y el ";" no funciona pues solo ejecuta la primera parte).
If you can **upload** a **.htaccess**, then you can **configure** several things and even execute code (configuring that files with extension .htaccess can be **executed**).
If yo are debugging a PHP application you can globally enable error printing in`/etc/php5/apache2/php.ini` adding `display_errors = On` and restart apache : `sudo systemctl restart apache2`
If you see that **Xdebug** is **enabled** in a `phpconfig()` output you should try to get RCE via [https://github.com/nqxcode/xdebug-exploit](https://github.com/nqxcode/xdebug-exploit)
lt;>/'^'{{{{'; --> _GET` `${$_}[_](${$_}[__]); --> $_GET[_]($_GET[__])` `So, the function is inside $_GET[_] and the parameter is inside $_GET[__]` http --form POST "http://victim.com/index.php?_=system&__=$CMD" "input=$CODE"
<summary><strong>Support HackTricks and get benefits!</strong></summary>
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