Vulnerability-Lookup

RUSTSEC-2021-0077 (CVE-2021-38196)

Vulnerability from osv_rustsec – Published: 2021-07-22 12:00 – Updated: 2023-06-13 13:10 – Source website

Summary

`better-macro` has deliberate RCE to prove a point

Details

better-macro is a fake crate which is "Proving A Point" that proc-macros can run arbitrary code. This is not a particularly novel or interesting observation.

It currently opens https://github.com/raycar5/better-macro/blob/master/doc/hi.md which doesn't appear to have any malicious content, but there's no guarantee that will remain the case.

This crate has no useful functionality, and should not be used.

References

URL

Type

	https://crates.io/crates/better-macro	PACKAGE
	https://rustsec.org/advisories/RUSTSEC-2021-0077.html	ADVISORY
	https://github.com/raycar5/better-macro/blob/24ff…	WEB

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "code-execution"
        ],
        "cvss": null,
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [
            "better_macro::println"
          ],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "better-macro",
        "purl": "pkg:cargo/better-macro"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2021-38196",
    "GHSA-79wf-qcqv-r22r"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "[better-macro](https://crates.io/crates/better-macro) is a fake crate which is\n\"Proving A Point\" that proc-macros can run arbitrary code. This is not a particularly\nnovel or interesting observation.\n\nIt currently opens `https://github.com/raycar5/better-macro/blob/master/doc/hi.md`\nwhich doesn\u0027t appear to have any malicious content, but there\u0027s no guarantee that\nwill remain the case.\n\nThis crate has no useful functionality, and should not be used.",
  "id": "RUSTSEC-2021-0077",
  "modified": "2023-06-13T13:10:24Z",
  "published": "2021-07-22T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/better-macro"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2021-0077.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/raycar5/better-macro/blob/24ff1702397b9c19bbfa4c660e2316cd77d3b900/src/lib.rs#L36-L38"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "`better-macro` has deliberate RCE to prove a point"
}

CVE-2021-38196 (GCVE-0-2021-38196)

Vulnerability from cvelistv5 – Published: 2021-08-08 05:07 – Updated: 2024-08-04 01:37

Summary

An issue was discovered in the better-macro crate through 2021-07-22 for Rust. It intentionally demonstrates that remote attackers can execute arbitrary code via proc-macros, and otherwise has no legitimate purpose.

Severity

No CVSS data available.

CWE

Assigner

mitre CNA under the mitre root

CNA scorecard E 28/100 over 2350 records in the last 180 days details

References

2 references

URL	Tags
https://rustsec.org/advisories/RUSTSEC-2021-0077.html	x_refsource_MISC
https://raw.githubusercontent.com/rustsec/advisor…	x_refsource_MISC

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T01:37:16.252Z",
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            "url": "https://rustsec.org/advisories/RUSTSEC-2021-0077.html"
          },
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            ],
            "url": "https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/better-macro/RUSTSEC-2021-0077.md"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
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      "references": [
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          "url": "https://rustsec.org/advisories/RUSTSEC-2021-0077.html"
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          ],
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        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2021-38196",
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GHSA-79WF-QCQV-R22R

Vulnerability from github – Published: 2021-08-25 20:56 – Updated: 2021-08-18 21:21

Summary

Remote code execution in better-macro

Details

Severity

9.8 (Critical)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "better-macro"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "1.0.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-38196"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-08-18T21:21:03Z",
    "nvd_published_at": "2021-08-08T06:15:00Z",
    "severity": "HIGH"
  },
  "details": "An issue was discovered in the better-macro crate through 2021-07-22 for Rust. It intentionally demonstrates that remote attackers can execute arbitrary code via proc-macros, and otherwise has no legitimate purpose.",
  "id": "GHSA-79wf-qcqv-r22r",
  "modified": "2021-08-18T21:21:03Z",
  "published": "2021-08-25T20:56:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-38196"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/raycar5/better-macro"
    },
    {
      "type": "WEB",
      "url": "https://github.com/raycar5/better-macro/blob/24ff1702397b9c19bbfa4c660e2316cd77d3b900/src/lib.rs#L36-L38"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2021-0077.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Remote code execution in better-macro"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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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-2021-0077 (CVE-2021-38196)

CVE-2021-38196 (GCVE-0-2021-38196)

GHSA-79WF-QCQV-R22R

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Vulnerability timeline

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