Vulnerability-Lookup

FKIE_CVE-2020-24722

Vulnerability from fkie_nvd - Published: 2020-10-07 15:15 - Updated: 2026-06-17 03:06

Severity

5.9 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Summary

An issue was discovered in the GAEN (aka Google/Apple Exposure Notifications) protocol through 2020-10-05, as used in COVID-19 applications on Android and iOS. The encrypted metadata block with a TX value lacks a checksum, allowing bitflipping to amplify a contamination attack. This can cause metadata deanonymization and risk-score inflation. NOTE: the vendor's position is "We do not believe that TX power authentication would be a useful defense against relay attacks.

References

URL	Tags
cve@mitre.org	http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html	Exploit, Third Party Advisory, VDB Entry
cve@mitre.org	http://seclists.org/fulldisclosure/2020/Oct/12	Exploit, Mailing List, Third Party Advisory
cve@mitre.org	https://blog.google/inside-google/company-announcements/update-exposure-notifications	Third Party Advisory
cve@mitre.org	https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations	Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html	Exploit, Third Party Advisory, VDB Entry
af854a3a-2127-422b-91ae-364da2661108	http://seclists.org/fulldisclosure/2020/Oct/12	Exploit, Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://blog.google/inside-google/company-announcements/update-exposure-notifications	Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations	Third Party Advisory

Impacted products

	Vendor	Product	Version
	exposure_notifications_project	exposure_notifications	*
	exposure_notifications_project	exposure_notifications	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:exposure_notifications_project:exposure_notifications:*:*:*:*:*:android:*:*",
              "matchCriteriaId": "59CFB73A-D00F-4527-BC13-DA45DE5F7175",
              "versionEndIncluding": "2020-10-05",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:exposure_notifications_project:exposure_notifications:*:*:*:*:*:iphone_os:*:*",
              "matchCriteriaId": "232A4EE9-1F2B-4672-BEA7-1663E87F6A0B",
              "versionEndIncluding": "2020-10-05",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [
    {
      "sourceIdentifier": "cve@mitre.org",
      "tags": [
        "disputed"
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in the GAEN (aka Google/Apple Exposure Notifications) protocol through 2020-10-05, as used in COVID-19 applications on Android and iOS. The encrypted metadata block with a TX value lacks a checksum, allowing bitflipping to amplify a contamination attack. This can cause metadata deanonymization and risk-score inflation. NOTE: the vendor\u0027s position is \"We do not believe that TX power authentication would be a useful defense against relay attacks."
    },
    {
      "lang": "es",
      "value": "**EN DISPUTA** Se detect\u00f3 un problema en el protocolo GAEN (tambi\u00e9n se conoce como Google/Apple Exposure Notifications) hasta el 05/10/2020, tal como es usado en las aplicaciones COVID-19 en Android e iOS.\u0026#xa0;El bloque de metadatos cifrados con un valor TX carece de un checksum, permitiendo a bitflipping amplificar un ataque de contaminaci\u00f3n.\u0026#xa0;Esto puede causar una desanonimizaci\u00f3n de los metadatos y la inflaci\u00f3n de la puntuaci\u00f3n de riesgo.\u0026#xa0;NOTA: la posici\u00f3n del proveedor es \"No creemos que la autenticaci\u00f3n de energ\u00eda TX sea una defensa \u00fatil contra los ataques de retransmisi\u00f3n\""
    }
  ],
  "id": "CVE-2020-24722",
  "lastModified": "2026-06-17T03:06:02.220",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "LOW",
        "cvssData": {
          "accessComplexity": "HIGH",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 2.6,
          "confidentialityImpact": "NONE",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:H/Au:N/C:N/I:P/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 4.9,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2020-10-07T15:15:12.553",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Exploit",
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "http://seclists.org/fulldisclosure/2020/Oct/12"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://blog.google/inside-google/company-announcements/update-exposure-notifications"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "http://seclists.org/fulldisclosure/2020/Oct/12"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://blog.google/inside-google/company-announcements/update-exposure-notifications"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/google/exposure-notifications-internals/blob/main/en-risks-and-mitigations-faq.md#additional-considerations"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-294"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2020-24722 (GCVE-0-2020-24722)

Vulnerability from cvelistv5 – Published: 2020-10-07 14:07 – Updated: 2024-08-04 15:19 Disputed

Summary

Severity

No CVSS data available.

CWE

Assigner

mitre mitre root

References

4 references

URL	Tags
https://blog.google/inside-google/company-announc…	x_refsource_MISC
http://seclists.org/fulldisclosure/2020/Oct/12	x_refsource_MISC
https://github.com/google/exposure-notifications-…	x_refsource_MISC
http://packetstormsecurity.com/files/159496/GAEN-…	x_refsource_MISC

Show details on NVD website

JSON

To clipboard

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        "providerMetadata": {
          "dateUpdated": "2024-08-04T15:19:09.383Z",
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            "url": "https://blog.google/inside-google/company-announcements/update-exposure-notifications"
          },
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          },
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            "url": "http://packetstormsecurity.com/files/159496/GAEN-Protocol-Metadata-Deanonymization-Risk-Score-Inflation.html"
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        ],
        "title": "CVE Program Container"
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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.

Detection rules are retrieved from Rulezet.

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.