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GHSA-5JJV-X4FQ-QJWP

Vulnerability from github – Published: 2020-10-05 15:48 – Updated: 2023-05-16 16:18
VLAI
Summary
Possible timing attack in derivation_endpoint
Details

Impact

When using the derivation_endpoint plugin, it's possible for the attacker to use a timing attack to guess the signature of the derivation URL.

Patches

The problem has been fixed by comparing sent and calculated signature in constant time, using Rack::Utils.secure_compare. Users using the derivation_endpoint plugin are urged to upgrade to Shrine 3.3.0 or greater.

Workarounds

Users of older Shrine versions can apply the following monkey-patch after loading the derivation_endpoint plugin:

class Shrine
  class UrlSigner
    def verify_signature(string, signature)
      if signature.nil?
        fail InvalidSignature, "missing \"signature\" param"
      elsif !Rack::Utils.secure_compare(signature, generate_signature(string))
        fail InvalidSignature, "provided signature does not match the calculated signature"
      end
    end
  end
end

References

You can read more about timing attacks here.

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "shrine"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2020-15237"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-203",
      "CWE-208"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2020-10-05T15:46:53Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nWhen using the `derivation_endpoint` plugin, it\u0027s possible for the attacker to use a timing attack to guess the signature of the derivation URL.\n\n### Patches\n\nThe problem has been fixed by comparing sent and calculated signature in constant time, using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine 3.3.0 or greater.\n\n### Workarounds\n\nUsers of older Shrine versions can apply the following monkey-patch after loading the `derivation_endpoint` plugin:\n\n```rb\nclass Shrine\n  class UrlSigner\n    def verify_signature(string, signature)\n      if signature.nil?\n        fail InvalidSignature, \"missing \\\"signature\\\" param\"\n      elsif !Rack::Utils.secure_compare(signature, generate_signature(string))\n        fail InvalidSignature, \"provided signature does not match the calculated signature\"\n      end\n    end\n  end\nend\n```\n\n### References\n\nYou can read more about timing attacks [here](https://en.wikipedia.org/wiki/Timing_attack).",
  "id": "GHSA-5jjv-x4fq-qjwp",
  "modified": "2023-05-16T16:18:49Z",
  "published": "2020-10-05T15:48:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/shrinerb/shrine/security/advisories/GHSA-5jjv-x4fq-qjwp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-15237"
    },
    {
      "type": "WEB",
      "url": "https://github.com/shrinerb/shrine/commit/1b27090ce31543bf39f186c20ea47c8250fca2f0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/shrine/CVE-2020-15237.yml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/shrinerb/shrine"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Possible timing attack in derivation_endpoint"
}



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