Описание
yt-dlp: --exec command injection when using %q in yt-dlp on Windows (Bypass of CVE-2023-40581)
Summary
The patch that addressed CVE-2023-40581 attempted to prevent RCE when using --exec with %q by replacing double quotes with two double quotes.
However, this escaping is not sufficient, and still allows expansion of environment variables.
Support for output template expansion in --exec, along with this vulnerable behavior, was added to yt-dlp in version 2021.04.11.
Patches
yt-dlp version 2024.04.09 fixes this issue by properly escaping %. It replaces them with %%cd:~,%, a variable that expands to nothing, leaving only the leading percent.
Workarounds
It is recommended to upgrade yt-dlp to version 2024.04.09 as soon as possible. Also, always be careful when using --exec, because while this specific vulnerability has been patched, using unvalidated input in shell commands is inherently dangerous.
For Windows users who are not able to upgrade:
- Avoid using any output template expansion in
--execother than{}(filepath). - If expansion in
--execis needed, verify the fields you are using do not contain%,",|or&. - Instead of using
--exec, write the info json and load the fields from it instead.
Details
When escaping variables, the following code is used for Windows.
yt_dlp/compat/__init__.py line 31-33
It replaces " with "" to balance out the quotes and keep quoting intact if non-allowed characters are included. However, the %CMDCMDLINE% variable can be used to generate a quote using %CMDCMDLINE:~-1%; since the value of %CMDCMDLINE% is the commandline with which cmd.exe was called, and it is always called with the command surrounded by quotes, %CMDCMDLINE:~-1% expands to ". After the quotes have been unbalanced, special characters are no longer quoted and commands can be executed:
References
Ссылки
- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-42h4-v29r-42qg
- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-hjq6-52gw-2g7p
- https://nvd.nist.gov/vuln/detail/CVE-2024-22423
- https://github.com/yt-dlp/yt-dlp/commit/de015e930747165dbb8fcd360f8775fd973b7d6e
- https://github.com/yt-dlp/yt-dlp/commit/ff07792676f404ffff6ee61b5638c9dc1a33a37a
- https://github.com/yt-dlp/yt-dlp/releases/tag/2021.04.11
- https://github.com/yt-dlp/yt-dlp/releases/tag/2024.04.09
- https://www.kb.cert.org/vuls/id/123335
Пакеты
yt-dlp
>= 2021.04.11, < 2024.04.09
2024.04.09
Связанные уязвимости
yt-dlp is a youtube-dl fork with additional features and fixes. The patch that addressed CVE-2023-40581 attempted to prevent RCE when using `--exec` with `%q` by replacing double quotes with two double quotes. However, this escaping is not sufficient, and still allows expansion of environment variables. Support for output template expansion in `--exec`, along with this vulnerable behavior, was added to `yt-dlp` in version 2021.04.11. yt-dlp version 2024.04.09 fixes this issue by properly escaping `%`. It replaces them with `%%cd:~,%`, a variable that expands to nothing, leaving only the leading percent. It is recommended to upgrade yt-dlp to version 2024.04.09 as soon as possible. Also, always be careful when using `--exec`, because while this specific vulnerability has been patched, using unvalidated input in shell commands is inherently dangerous. For Windows users who are not able to upgrade, avoid using any output template expansion in `--exec` other than `{}` (filepath); if exp...
yt-dlp is a youtube-dl fork with additional features and fixes. The patch that addressed CVE-2023-40581 attempted to prevent RCE when using `--exec` with `%q` by replacing double quotes with two double quotes. However, this escaping is not sufficient, and still allows expansion of environment variables. Support for output template expansion in `--exec`, along with this vulnerable behavior, was added to `yt-dlp` in version 2021.04.11. yt-dlp version 2024.04.09 fixes this issue by properly escaping `%`. It replaces them with `%%cd:~,%`, a variable that expands to nothing, leaving only the leading percent. It is recommended to upgrade yt-dlp to version 2024.04.09 as soon as possible. Also, always be careful when using `--exec`, because while this specific vulnerability has been patched, using unvalidated input in shell commands is inherently dangerous. For Windows users who are not able to upgrade, avoid using any output template expansion in `--exec` other than `{}` (filepath); if expans
yt-dlp is a youtube-dl fork with additional features and fixes. The pa ...
Уязвимость утилиты загрузки аудио и видео yt-dlp, существующая из-за непринятия мер по нейтрализации специальных элементов, используемых в команде операционной системы, позволяющая нарушителю выполнить произвольный код