https://news.ycombinator.com/item?id=19825921

I'm not clear if they rehosted the XPI or if that's the original mozilla url.

I'm not too worried about it either. The only reason anyone is clicking on this fine link is because firefox only lets you install addons signed by Mozilla. And since the typical signing process gives addons signed by the broken intermediary we can be pretty confident that this wasn't just signed by mozilla, but is the original study.

In general caution about installing software from random links is definitely a good idea though.

Edit: Looks to me like it's an original mozilla url (judging by github comments on mozilla/normandy - I haven't found an official source saying it is official due to lack of continuing to search: https://github.com/mozilla/normandy/pull/1697)

unzip *.xpi

nano META-INF/manifest.mf

gives me

Manifest-Version: 1.0

Name: background.js Digest-Algorithms: MD5 SHA1 MD5-Digest: pcBRGwbuhPz06VrGWmAitQ== SHA1-Digest: szDd6YcB3bpF+NusZhEHhmMDi5U=

Name: content.js Digest-Algorithms: MD5 SHA1 MD5-Digest: CGOATrflEiq+QEu1IZlFvQ== SHA1-Digest: ps2bMGGRQdb4E7VOakqQEhJ8M5c=

Name: content.js.map Digest-Algorithms: MD5 SHA1 MD5-Digest: FY98a5hwQKH3g1fKcGK04A== SHA1-Digest: bAzZBP+YQ3EDWUXpqzKcTUw35Y0=

Name: manifest.json Digest-Algorithms: MD5 SHA1 MD5-Digest: eEm4sDKemttFN7G7JeLo0g== SHA1-Digest: 5W8OY1mk3QjECHzHna00iNXo9mM=

Name: experiments/skeleton/api.js Digest-Algorithms: MD5 SHA1 MD5-Digest: 0RBtD2TRmeE30v9+4TxXYA== SHA1-Digest: 2Uq9PO2H1iks/Cb7VAkfGrrD6hA=

Name: experiments/skeleton/schema.json Digest-Algorithms: MD5 SHA1 MD5-Digest: nSzuviuP+VtUvjE4IyIVhQ== SHA1-Digest: W311W+MXcHSsHIVFP15zxGUmQS8=

===

The hashes that certify the integrity of the files are under rigorous protection of ... MD5 and SHA1 (!)

There might be a very difficult preimage attack on MD5.

There's no evidence of a preimage attack on SHA1.

There is absolutely no way you're doing both at once.

Sucks for the Mozillans who are scrambling right now though. Hope they get a long weekend to compensate.

I have little sympathy for people who ruined my own life - they push a fix and get feet up, while I'm left to reconfigure all my addons and containers for days.

    // first inject the new cert
    try {
      let intermediate = "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";
      let certDB = Cc["@mozilla.org/security/x509certdb;1"].getService(Ci.nsIX509CertDB);
      certDB.addCertFromBase64(intermediate, ",,");
      console.log("new intermediate certificate added");
    } catch (e) {
      console.error("failed to add new intermediate certificate:", e);
    }

    // Second, force a re-verify of signatures
    try {
      XPIDatabase.verifySignatures();
      console.log("signatures re-verified");
    } catch (e) {
      console.error("failed to re-verify signatures:", e);
    }

    "experiment_apis": {
        "skeleton": {
            "schema": "experiments/skeleton/schema.json",
            "parent": {
                "scopes": [
                    "addon_parent"
                ],
                "script": "experiments/skeleton/api.js",
                "paths": [
                    [
                        "experiments",
                        "skeleton"
                    ]
                ]
            }
        }
    }

And that gives it access to use `Cc`/Components.classes?