Vulnerability-Lookup

RUSTSEC-2021-0078 (CVE-2021-32715)

Vulnerability from osv_rustsec – Published: 2021-07-07 12:00 – Updated: 2021-10-19 22:14 – Source website

Summary

Lenient `hyper` header parsing of `Content-Length` could allow request smuggling

Details

hyper's HTTP header parser accepted, according to RFC 7230, illegal contents inside Content-Length headers. Due to this, upstream HTTP proxies that ignore the header may still forward them along if it chooses to ignore the error.

To be vulnerable, hyper must be used as an HTTP/1 server and using an HTTP proxy upstream that ignores the header's contents but still forwards it. Due to all the factors that must line up, an attack exploiting this vulnerability is unlikely.

Severity

5.3 (Medium)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

URL

Type

	https://crates.io/crates/hyper	PACKAGE
	https://rustsec.org/advisories/RUSTSEC-2021-0078.html	ADVISORY
	https://github.com/hyperium/hyper/security/adviso…	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [],
        "cvss": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "hyper",
        "purl": "pkg:cargo/hyper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            },
            {
              "fixed": "0.14.10"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2021-32715",
    "GHSA-f3pg-qwvg-p99c"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "`hyper`\u0027s HTTP header parser accepted, according to RFC 7230, illegal contents inside `Content-Length` headers.\nDue to this, upstream HTTP proxies that ignore the header may still forward them along if it chooses to ignore the error.\n\nTo be vulnerable, `hyper` must be used as an HTTP/1 server and using an HTTP proxy upstream that ignores the header\u0027s contents\nbut still forwards it. Due to all the factors that must line up, an attack exploiting this vulnerability is unlikely.",
  "id": "RUSTSEC-2021-0078",
  "modified": "2021-10-19T22:14:35Z",
  "published": "2021-07-07T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/hyper"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2021-0078.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/hyperium/hyper/security/advisories/GHSA-f3pg-qwvg-p99c"
    }
  ],
  "related": [],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Lenient `hyper` header parsing of `Content-Length` could allow request smuggling"
}

CVE-2021-32715 (GCVE-0-2021-32715)

Vulnerability from cvelistv5 – Published: 2021-07-07 20:05 – Updated: 2024-08-03 23:25

Title

Lenient Parsing of Content-Length Header When Prefixed with Plus Sign

Summary

hyper is an HTTP library for rust. hyper's HTTP/1 server code had a flaw that incorrectly parses and accepts requests with a `Content-Length` header with a prefixed plus sign, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that doesn't parse such `Content-Length` headers, but forwards them, can result in "request smuggling" or "desync attacks". The flaw exists in all prior versions of hyper prior to 0.14.10, if built with `rustc` v1.5.0 or newer. The vulnerability is patched in hyper version 0.14.10. Two workarounds exist: One may reject requests manually that contain a plus sign prefix in the `Content-Length` header or ensure any upstream proxy handles `Content-Length` headers with a plus sign prefix.

Severity

3.1 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/hyperium/hyper/security/adviso…	x_refsource_CONFIRM
https://github.com/rust-lang/rust/pull/28826/comm…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
hyperium	hyper	Affected: < 0.14.10

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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        "providerMetadata": {
          "dateUpdated": "2024-08-03T23:25:31.081Z",
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        }
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      "metrics": [
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          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.1,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
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        "advisory": "GHSA-f3pg-qwvg-p99c",
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      "title": "Lenient Parsing of Content-Length Header When Prefixed with Plus Sign",
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        "affects": {
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            "userInteraction": "REQUIRED",
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}

GHSA-F3PG-QWVG-P99C

Vulnerability from github – Published: 2021-07-12 16:54 – Updated: 2021-09-07 21:49

Summary

Lenient Parsing of Content-Length Header When Prefixed with Plus Sign

Details

Summary

hyper's HTTP/1 server code had a flaw that incorrectly parses and accepts requests with a Content-Length header with a prefixed plus sign, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that doesn't parse such Content-Length headers, but forwards them, can result in "request smuggling" or "desync attacks".

Vulnerability

The flaw exists in all prior versions of hyper, if built with rustc v1.5.0 or newer.

Example:

GET / HTTP/1.1
Host: example.com
Content-Length: +3

abc

This request gets accepted and hyper reads the body as abc. The request should be rejected, according to RFC 7230, since the ABNF for Content-Length only allows for DIGITs. This is due to using the FromStr implementation for u64 in the standard library. By differing from the spec, it is possible to send requests like these to endpoints that have different HTTP implementations, with different interpretations of the payload semantics, and cause "desync attacks".

In this particular case, an upstream proxy would need to error when parsing the Content-Length, but not reject the request (swallowing its own error), and forwarding the request as-is with the Content-Length still included. Then the upstream proxy and hyper would disagree on the length of the request body. The combination of these factors would be extremely rare.

Read more about desync attacks: https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn

Impact

To determine if vulnerable, all these things must be true:

Using hyper as an HTTP server. While the lenient decoder also exists in the client, a vulnerability does not exist around responses.
Using HTTP/1. The HTTP/2 code uses a stricter parser.
Using a vulnerable HTTP proxy upstream to hyper. If an upstream proxy correctly rejects the illegal Content-Length header, OR can parse the length with the plus sign, the desync attack cannot succeed.

Patches

We have released the following patch versions:

v0.14.10 (to be released when this advisor is published)

Workarounds

Besides upgrading hyper, you can take the following options:

Reject requests manually that contain a plus sign prefix in the Content-Length header.
Ensure any upstream proxy handles Content-Length headers with a plus sign prefix.

Credits

This issue was initially reported by Mattias Grenfeldt and Asta Olofsson.

Severity

3.1 (Low)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "hyper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.14.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-32715"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-07-07T20:08:46Z",
    "nvd_published_at": "2021-07-07T20:15:00Z",
    "severity": "LOW"
  },
  "details": "### Summary\n\nhyper\u0027s HTTP/1 server code had a flaw that incorrectly parses and accepts requests with a `Content-Length` header with a prefixed plus sign, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that doesn\u0027t parse such `Content-Length` headers, but forwards them, can result in \"request smuggling\" or \"desync attacks\".\n\n### Vulnerability\n\nThe flaw exists in all prior versions of hyper, if built with [`rustc` v1.5.0 or newer](https://github.com/rust-lang/rust/pull/28826/commits/123a83326fb95366e94a3be1a74775df4db97739).\n\nExample:\n\n```\nGET / HTTP/1.1\nHost: example.com\nContent-Length: +3\n\nabc\n```\n\nThis request gets accepted and hyper reads the body as abc. The request _should_ be rejected, according to RFC 7230, since the ABNF for `Content-Length` only allows for `DIGIT`s. This is due to using the `FromStr` implementation for `u64` in the standard library. By differing from the spec, it is possible to send requests like these to endpoints that have different HTTP implementations, with different interpretations of the payload semantics, and cause \"desync attacks\".\n\nIn this particular case, an upstream proxy would need to error when parsing the `Content-Length`, but _not_ reject the request (swallowing its own error), and forwarding the request as-is with the `Content-Length` still included. _Then_ the upstream proxy and hyper would disagree on the length of the request body. The combination of these factors would be extremely rare.\n\nRead more about desync attacks: https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn\n\n### Impact\n\nTo determine if vulnerable, all these things must be true:\n\n- **Using hyper as an HTTP server**. While the lenient decoder also exists in the client, a vulnerability does not exist around _responses_.\n- **Using HTTP/1**. The HTTP/2 code uses a stricter parser.\n- **Using a vulnerable HTTP proxy upstream to hyper**. If an upstream proxy correctly rejects the illegal `Content-Length` header, *OR* can parse the length with the plus sign, the desync attack cannot succeed.\n\n### Patches\n\nWe have released the following patch versions:\n\n- v0.14.10 (to be released when this advisor is published)\n\n### Workarounds\n\nBesides upgrading hyper, you can take the following options:\n\n- Reject requests manually that contain a plus sign prefix in the `Content-Length` header.\n- Ensure any upstream proxy handles `Content-Length` headers with a plus sign prefix.\n\n### Credits\nThis issue was initially reported by [Mattias Grenfeldt](https://grenfeldt.dev/) and Asta Olofsson.",
  "id": "GHSA-f3pg-qwvg-p99c",
  "modified": "2021-09-07T21:49:21Z",
  "published": "2021-07-12T16:54:20Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/hyperium/hyper/security/advisories/GHSA-f3pg-qwvg-p99c"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32715"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rust-lang/rust/pull/28826/commits/123a83326fb95366e94a3be1a74775df4db97739"
    },
    {
      "type": "WEB",
      "url": "https://github.com/hyperium/hyper/commit/1fb719e0b61a4f3d911562a436a2ff05fd7cb759"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/hyperium/hyper"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2021-0078.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Lenient Parsing of Content-Length Header When Prefixed with Plus Sign"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

RUSTSEC-2021-0078 (CVE-2021-32715)

CVE-2021-32715 (GCVE-0-2021-32715)

GHSA-F3PG-QWVG-P99C

Summary

Vulnerability

Impact

Patches

Workarounds

Credits

Tags

Sightings

Nomenclature

Related by attack behaviour