Описание
PHAR deserialization allowing remote code execution
Description
snappy is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the file_exists() function. If an attacker can upload files of any type to the server he can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution especially when snappy is used with frameworks with documented POP chains like Laravel/Symfony vulnerable developer code. If user can control the output file from the generateFromHtml() function, it will invoke deserialization.
Proof of Concept
Install Snappy via composer require knplabs/knp-snappy. After that, under snappy directory, create an index.php file with this vulnerable code.
As an attacker, we going to generate the malicious phar using this script.
Then run these command to generate the file
Then execute index.php with php index.php. You will see a file named pwned will be created. Noted that attacker can upload a file with any extension such as .png or .jpeg. So poc.jpeg also will do the trick.
Impact
This vulnerability is capable of remote code execution if Snappy is used with frameworks or developer code with vulnerable POP chains.
Occurences
References
Ссылки
- https://github.com/KnpLabs/snappy/security/advisories/GHSA-gq6w-q6wh-jggc
- https://nvd.nist.gov/vuln/detail/CVE-2023-28115
- https://github.com/KnpLabs/snappy/pull/469
- https://github.com/KnpLabs/snappy/commit/1ee6360cbdbea5d09705909a150df7963a88efd6
- https://github.com/KnpLabs/snappy/commit/b66f79334421c26d9c244427963fa2d92980b5d3
- https://github.com/FriendsOfPHP/security-advisories/blob/master/knplabs/knp-snappy/CVE-2023-28115.yaml
- https://github.com/KnpLabs/snappy/blob/5126fb5b335ec929a226314d40cd8dad497c3d67/src/Knp/Snappy/AbstractGenerator.php#L670
- https://github.com/KnpLabs/snappy/releases/tag/v1.4.2
- https://github.com/advisories/GHSA-gq6w-q6wh-jggc
- https://huntr.dev/bounties/0bdddc12-ff67-4815-ab9f-6011a974f48e
Пакеты
knplabs/knp-snappy
< 1.4.2
1.4.2
Связанные уязвимости
Snappy is a PHP library allowing thumbnail, snapshot or PDF generation from a url or a html page. Prior to version 1.4.2, Snappy is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the `file_exists()` function. If an attacker can upload files of any type to the server he can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution especially when snappy is used with frameworks with documented POP chains like Laravel/Symfony vulnerable developer code. If a user can control the output file from the `generateFromHtml()` function, it will invoke deserialization. This vulnerability is capable of remote code execution if Snappy is used with frameworks or developer code with vulnerable POP chains. It has been fixed in version 1.4.2.
Snappy is a PHP library allowing thumbnail, snapshot or PDF generation from a url or a html page. Prior to version 1.4.2, Snappy is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the `file_exists()` function. If an attacker can upload files of any type to the server he can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution especially when snappy is used with frameworks with documented POP chains like Laravel/Symfony vulnerable developer code. If a user can control the output file from the `generateFromHtml()` function, it will invoke deserialization. This vulnerability is capable of remote code execution if Snappy is used with frameworks or developer code with vulnerable POP chains. It has been fixed in version 1.4.2.
Snappy is a PHP library allowing thumbnail, snapshot or PDF generation ...
Уязвимость функции generateFromHtml() библиотеки PHP Snappy, позволяющая нарушителю выполнить произвольный код