ghsa-79w7-vh3h-8g4j
Vulnerability from github
Summary
yt-dlp does not limit the extensions of downloaded files, which could lead to arbitrary filenames being created in the download folder (and path traversal on Windows). Since yt-dlp also reads config from the working directory (and on Windows executables will be executed from the yt-dlp directory) this could lead to arbitrary code being executed.
Patches
yt-dlp version 2024.07.01 fixes this issue by whitelisting the allowed extensions.
This means some very uncommon extensions might not get downloaded; however, it will also limit the possible exploitation surface.
Workarounds
It is recommended to upgrade yt-dlp to version 2024.07.01 as soon as possible, always have .%(ext)s at the end of the output template, and make sure you trust the websites that you are downloading from. Also, make sure to never download to a directory within PATH or other sensitive locations like your user directory, system32, or other binaries locations.
For users not able to upgrade:
- Make sure the extension of the media to download is a common video/audio/sub/... one
- Try to avoid the generic extractor (--ies default,-generic)
- Keep the default output template (-o "%(title)s [%(id)s].%(ext)s)
- Omit any of the subtitle options (--write-subs, --write-auto-subs, --all-subs, --write-srt)
- Use --ignore-config --config-location ... to not load config from common locations
Details
One potential exploitation might look like this:
From a mimetype we do not know, we default to trimming the leading bit and using the remainder. Given a webpage that contains ```html
{ "@context": "https://schema.org", "@type": "VideoObject", "name": "ffmpeg", "encodingFormat": "video/exe", "contentUrl": "https://example.com/video.mp4" }``
this will try and download a file calledffmpeg.exe(-o "%(title)s.%(ext)s).ffmpeg.exe` will be searched for in the current directory, and so upon the next run arbitrary code can be executed.
Alternatively, when engineering a file called yt-dlp.conf to be created, the config file could contain --exec ... and so would also execute arbitrary code.
Acknowledgement
A big thanks to @JarLob for independently finding a new application of the same underlying issue. More can be read about on the dedicated GitHub Security Lab disclosure here: Path traversal saving subtitles (GHSL-2024-090)
References
- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j
- https://nvd.nist.gov/vuln/detail/CVE-2024-38519
- https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01
- https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a
- https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "yt-dlp"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2024.07.01"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-38519"
],
"database_specific": {
"cwe_ids": [
"CWE-434",
"CWE-669"
],
"github_reviewed": true,
"github_reviewed_at": "2024-07-02T15:58:35Z",
"nvd_published_at": "2024-07-02T14:15:13Z",
"severity": "HIGH"
},
"details": "### Summary\n`yt-dlp` does not limit the extensions of downloaded files, which could lead to arbitrary filenames being created in the download folder (and path traversal on Windows). Since `yt-dlp` also reads config from the working directory (and on Windows executables will be executed from the yt-dlp directory) this could lead to arbitrary code being executed.\n\n### Patches\n`yt-dlp` version 2024.07.01 fixes this issue by whitelisting the allowed extensions.\nThis means some very uncommon extensions might not get downloaded; however, it will also limit the possible exploitation surface.\n\n### Workarounds\nIt is recommended to upgrade yt-dlp to version 2024.07.01 as soon as possible, **always** have `.%(ext)s` at the end of the output template, and make sure you trust the websites that you are downloading from. Also, make sure to never download to a directory within PATH or other sensitive locations like your user directory, `system32`, or other binaries locations.\n\nFor users not able to upgrade:\n- Make sure the extension of the media to download is a common video/audio/sub/... one\n- Try to avoid the generic extractor (`--ies default,-generic`)\n- Keep the default output template (`-o \"%(title)s [%(id)s].%(ext)s`)\n- Omit any of the subtitle options (`--write-subs`, `--write-auto-subs`, `--all-subs`, `--write-srt`)\n- Use `--ignore-config --config-location ...` to not load config from common locations\n\n### Details\nOne potential exploitation might look like this:\n\nFrom a mimetype we do not know, we default to trimming the leading bit and using the remainder. Given a webpage that contains\n```html\n\u003cscript type=\"application/ld+json\"\u003e\n{\n \"@context\": \"https://schema.org\",\n \"@type\": \"VideoObject\",\n \"name\": \"ffmpeg\",\n \"encodingFormat\": \"video/exe\",\n \"contentUrl\": \"https://example.com/video.mp4\"\n}\n\u003c/script\u003e\n```\nthis will try and download a file called `ffmpeg.exe` (`-o \"%(title)s.%(ext)s`).\n`ffmpeg.exe` will be searched for in the current directory, and so upon the next run arbitrary code can be executed.\n\nAlternatively, when engineering a file called `yt-dlp.conf` to be created, the config file could contain `--exec ...` and so would also execute arbitrary code.\n\n### Acknowledgement\nA big thanks to @JarLob for independently finding a new application of the same underlying issue.\nMore can be read about on the dedicated GitHub Security Lab disclosure here: [Path traversal saving subtitles (GHSL-2024-090)](\u003chttps://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp\u003e)\n\n### References\n- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j\n- https://nvd.nist.gov/vuln/detail/CVE-2024-38519\n- https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01\n- https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a\n- https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp\n",
"id": "GHSA-79w7-vh3h-8g4j",
"modified": "2024-07-05T17:54:51Z",
"published": "2024-07-02T15:58:35Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/dirkf/youtube-dl/security/advisories/GHSA-22fp-mf44-f2mq"
},
{
"type": "WEB",
"url": "https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-38519"
},
{
"type": "WEB",
"url": "https://github.com/ytdl-org/youtube-dl/pull/32830"
},
{
"type": "WEB",
"url": "https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a"
},
{
"type": "WEB",
"url": "https://github.com/ytdl-org/youtube-dl/commit/d42a222ed541b96649396ef00e19552aef0f09ec"
},
{
"type": "PACKAGE",
"url": "https://github.com/yt-dlp/yt-dlp"
},
{
"type": "WEB",
"url": "https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01"
},
{
"type": "ADVISORY",
"url": "https://securitylab.github.com/advisories/GHSL-2024-089_youtube-dl"
},
{
"type": "ADVISORY",
"url": "https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "yt-dlp File system modification and RCE through improper file-extension sanitization"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.