quixel-bridge

maintainer faith · 4 votes · scanned 2026-08-03 00:08:14.047287

MEDIUM

Why flagged The package downloads a prebuilt AppImage binary from d2shgxa8i058x8.cloudfront.net, which is a CloudFront CDN distribution. CloudFront is used by many legitimate vendors including Epic Games/Quixel (who owns Megascans/Bridge), so this is plausibly the official distribution host. However, it is not a canonical, easily verifiable official domain (like quixel.com directly), and there is no way to confirm this CloudFront distribution belongs to Quixel without additional research. The AppImage is executed during prepare() via --appimage-extract and then installed and symlinked into /usr/bin, meaning it runs as a full binary on the user's system. A sha256sum is provided, which mitigates substitution risk somewhat, but the hash only protects against in-transit tampering — if the upstream host is compromised or the CDN bucket is misconfigured, the hash in the PKGBUILD would need to be updated to reflect any malicious change. Overall this is a standard pattern for AppImage packaging in the AUR (medium risk: prebuilt binary from a CDN that is plausibly official but not definitively verifiable), not a clear attack.

Triggered rules

MEDIUM source=() URL on a non-standard host source_untrusted_domain

One or more source=() URLs point to a host outside the trusted allowlist (github.com, gitlab.com, codeberg.org, pypi.org, …).

PKGBUILD:15 source_x86_64=("https://d2shgxa8i058x8.cloudfront.net/bridge/linux/${_appimage}")

MEDIUM AI review llm_review

An AI model (anthropic/claude-4.6-sonnet-20260217) reviewed this and agrees it is MEDIUM (confidence 72%): The package downloads a prebuilt AppImage binary from d2shgxa8i058x8.cloudfront.net, which is a CloudFront CDN distribution. CloudFront is used by many legitimate vendors including Epic Games/Quixel (who owns Megascans/Bridge), so this is plausibly the official distribution host. However, it is not a canonical, easily verifiable official domain (like quixel.com directly), and there is no way to confirm this CloudFront distribution belongs to Quixel without additional research. The AppImage is executed during prepare() via --appimage-extract and then installed and symlinked into /usr/bin, meaning it runs as a full binary on the user's system. A sha256sum is provided, which mitigates substitution risk somewhat, but the hash only protects against in-transit tampering — if the upstream host is compromised or the CDN bucket is misconfigured, the hash in the PKGBUILD would need to be updated to reflect any malicious change. Overall this is a standard pattern for AppImage packaging in the AUR (medium risk: prebuilt binary from a CDN that is plausibly official but not definitively verifiable), not a clear attack.

PKGBUILD

1 offending line(s) highlighted

      1# Maintainer: Valters Tomsons <valters.tomsons at protonmail dot com>
    
      2
    
      3_appimage="Bridge.AppImage"
    
      4_desktop="megascans-bridge.desktop"
    
      5
    
      6pkgname="quixel-bridge"
    
      7pkgver=2024.0.7
    
      8pkgrel=1
    
      9pkgdesc="A tool for browsing, searching, downloading, importing and exporting Megascans assets"
    
      10arch=('x86_64')
    
      11url="https://quixel.com/bridge"
    
      12license=('custom:Commercial')
    
      13depends=('zlib' 'hicolor-icon-theme')
    
      14options=(!strip)
    
      15source_x86_64=("https://d2shgxa8i058x8.cloudfront.net/bridge/linux/${_appimage}")
    
      16noextract=("${_appimage}")
    
      17sha256sums_x86_64=('08ac714c50949206a2bd7da187010ffb0a38267a5142c218a0665f0e29101770')
    
      18
    
      19prepare() {
    
      20    chmod +x "${_appimage}"
    
      21    ./"${_appimage}" --appimage-extract
    
      22}
    
      23
    
      24build() {
    
      25    # Adjust .desktop so it will work outside of AppImage container
    
      26    sed -i -E "s|Exec=AppRun|Exec=env DESKTOPINTEGRATION=false /usr/bin/${pkgname}|" \
    
      27        "squashfs-root/${_desktop}"
    
      28
    
      29    # Fix permissions; .AppImage permissions are 700 for all directories
    
      30    chmod -R a-x+rX squashfs-root/usr
    
      31}
    
      32
    
      33package() {
    
      34    # AppImage
    
      35    install -Dm755 "${srcdir}/${_appimage}" "${pkgdir}/opt/${pkgname}/${_appimage}"
    
      36
    
      37    # Desktop file
    
      38    install -Dm644 "${srcdir}/squashfs-root/${_desktop}" "${pkgdir}/usr/share/applications/${_desktop}"
    
      39
    
      40    # Icon Iimages
    
      41    install -dm755 "${pkgdir}/usr/share/"
    
      42    cp -a "${srcdir}/squashfs-root/usr/share/icons" "${pkgdir}/usr/share/"
    
      43
    
      44    # Symlink
    
      45    install -dm755 "${pkgdir}/usr/bin"
    
      46    ln -s "/opt/${pkgname}/${_appimage}" "${pkgdir}/usr/bin/${pkgname}"
    
      47}
    
      48

Scan history

Scanned at (UTC)	Severity	Rules
2026-08-03 00:08:14	MEDIUM	2
2026-08-02 00:16:08	MEDIUM	2
2026-08-01 00:11:18	MEDIUM	2
2026-07-31 00:14:10	MEDIUM	2
2026-07-30 00:17:23	MEDIUM	2
2026-07-29 00:25:53	MEDIUM	2
2026-07-28 00:07:28	MEDIUM	2
2026-07-27 00:24:32	MEDIUM	2
2026-07-26 00:07:32	MEDIUM	2
2026-07-25 00:13:44	MEDIUM	2
2026-07-24 00:02:28	MEDIUM	2
2026-07-23 00:14:47	MEDIUM	2
2026-07-22 00:29:32	MEDIUM	2
2026-07-21 00:24:15	MEDIUM	2
2026-07-20 00:19:49	MEDIUM	2
2026-07-19 00:17:08	MEDIUM	2
2026-07-18 00:14:48	MEDIUM	2
2026-07-17 00:06:16	MEDIUM	2
2026-07-16 00:05:41	MEDIUM	2
2026-07-15 00:09:25	MEDIUM	2