Analysing Assets.car file in iOS

This tool can extract a .car archive: https://github.com/steventroughtonsmith/cartool

Steps to extract archive:

Once you’ve downloaded the zip from github, compile it in Xcode to generate the command line tool. Then expand the Products group and right click on the cartool file and locate it in finder. You can then run the tool like so:

  • open terminal
  • cd /path/to/cartool
  • ./cartool /path/to/Assets.car /path/to/outputDirectory

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.

If you want to browse and extract asset catalogs, you can also use my app Asset Catalog Tinkerer

Asset Catalog Tinkerer screenshot

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