Analysing Assets.car file in iOS

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Run Apple’s assetutil:

xcrun --sdk iphoneos assetutil --info Assets.car

you’ll get a JSON description of each item in the file. Something like this:

  {
    "Height" : 60,
    "Scale" : 1,
    "RenditionName" : "D3801CE9-19F1-4CE9-97C6-7E1EFFFCAE89",
    "AssetType" : "Vector",
    "SizeOnDisk" : 10822,
    "Name" : "mailbox",
    "Idiom" : "universal",
    "Width" : 99
  },

Note the line "SizeOnDisk" : 10822.

This tool performs limited .car manipulation, run man assetutil for details.

The Assets.car seems to be a proprietary Apple’s archive that first appeared in iOS 7. A few utilities are able to extract its contents using the private class CUICatalog of the CoreUI framework:

  • acextract
  • ThemeEngine
  • iOS Asset Extractor
  • Asset Catalog Tinkerer

There is also an app that reads .car files: crunch 9$, 15 day trial

Running strings Assets.car returned 

@(#)PROGRAM:CoreUI  PROJECT:CoreUI-475.1.1
IBCocoaTouchImageCatalogTool-9.0

Running find inside Xcode-beta returned /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Overlays/IBCocoaTouchImageCatalogTool, which is a simulator executable (i386 + x86_64). Didn’t investigate any further but I bet that this tool could open .car archives if you run it inside the simulator.

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