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Thomas.G for NodeSecure

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JS-X-Ray 1.0


While I was working on the next release (0.6.0) of Node-Secure I thought that the AST analysis was getting bigger and bigger (and much more complicated too).

That's why I decided to separate all the analysis from the Node-secure project to allow easier maintenance and future enhancement. This also allows other projects to use my package if they need to!

This is how JS-X-RAY was born. I have chosen the word x-ray because in games this is often a feature that allow to see through the walls, I like to imagine my analysis as being able to see through the most common techniques (obfuscation, etc.).

The goal

One of the primary goals of this package is to be able to find any required Node.js dependencies in a given code. If the analysis is not able to follow a require statement then an unsafe-import warning will be throw.

The more time goes and the more I think to make my code generic to also detect patterns specific to the front.

So I think the code will evolve in this direction :)



Take the purescript-installer incident and specially the corrupted rate-map code.

One of the objectives of node-secure is to be able to quickly identify code with warnings and give a bunch of very useful informations to the developer.

In this case node-secure was able to detect the following dependencies:
append-type, fs, dl-tar.

const px = require.resolve(
Buffer.from([100, 108, 45, 116, 97, 114]).toString()
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My AST analysis has detected a Buffer.from and as converted the value to dl-tar itself. In this case an unsafe-import will be throw with the file name and the Source Location.


Take the Payload A in the event-stream incident.

So what's going on here?

  • 1) assign of process and require into new variables.
  • 2) hexa value.
  • 3) code obfuscated (all identifiers have a length of 1).

I'm working on a bench of experimental analysis and warnings to be able to detect similar cases to event-stream incident.

    "kind": "unsafe-assign",
    "start": { "line": 3, "column": 12 },
    "end": { "line": 3, "column": 23 },
    "value": "require"      
    "kind": "unsafe-assign",
    "start": { "line": 4, "column": 12 },
    "end": { "line": 4, "column": 23 },
    "value": "process"
    "kind": "hexa-value",
    "start": { "line": 9, "column": 20 },
    "end": { "line": 9, "column": 44 },
    "value": "./test/data"
    "kind": "short-ids",
    "start": { "line": 0, "column": 0 },
    "end": { "line": 0,"column": 0 },
    "value": 1
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However, A lot of packages may be detected as false positives (even if it's always better than nothing 😅). It will surely take time to discover and improve these parameters.


Still a LOT of work has to be done to be able to achieve an accurate analysis. Right now the analysis is capable of gathering a whole of very useful information (unsafe-regex, unused and missing dependencies etc.).

I am always very excited to experience new warnings because they can detect patterns and errors that are often (un)common. Step by step they also lead me to a better understanding of the most dangerous patterns of the ecosystem.

For example 90%+ of the false positive are always generated because of files that was not mean to be published on the npm registry (tests, coverage files, etc.).

Thanks for reading!

Best Regards,

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