Vulnerability-Lookup

CNVD-2021-51798

Vulnerability from cnvd - Published: 2021-07-19

Title

Nextcloud信任管理问题漏洞（CNVD-2021-51798）

Description

Nextcloud是德国Nextcloud公司的一套开源的自托管文件同步和共享的通信应用平台。 Nextcloud Android Client在3.16.1之前版本存在信任管理问题漏洞，该漏洞源于Nextcloud Android客户端跳过了一个涉及客户端检查私钥是否属于之前下载的公共证书的步骤。如果Nextcloud实例提供了一个恶意公钥，那么数据将为此密钥进行加密，从而可以被恶意参与者访问。攻击者可利用该漏洞获取敏感信息。

Severity

中

Patch Name

Nextcloud信任管理问题漏洞（CNVD-2021-51798）的补丁

Patch Description

Formal description

目前厂商已发布升级补丁以修复漏洞，补丁获取链接： https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736

Reference

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736

Impacted products

Name
Nextcloud Nextcloud Android Client <3.16.1

Show details on source website

JSON

To clipboard

{
  "cves": {
    "cve": {
      "cveNumber": "CVE-2021-32727",
      "cveUrl": "https://nvd.nist.gov/vuln/detail/CVE-2021-32727"
    }
  },
  "description": "Nextcloud\u662f\u5fb7\u56fdNextcloud\u516c\u53f8\u7684\u4e00\u5957\u5f00\u6e90\u7684\u81ea\u6258\u7ba1\u6587\u4ef6\u540c\u6b65\u548c\u5171\u4eab\u7684\u901a\u4fe1\u5e94\u7528\u5e73\u53f0\u3002\n\nNextcloud Android Client\u57283.16.1\u4e4b\u524d\u7248\u672c\u5b58\u5728\u4fe1\u4efb\u7ba1\u7406\u95ee\u9898\u6f0f\u6d1e\uff0c\u8be5\u6f0f\u6d1e\u6e90\u4e8eNextcloud Android\u5ba2\u6237\u7aef\u8df3\u8fc7\u4e86\u4e00\u4e2a\u6d89\u53ca\u5ba2\u6237\u7aef\u68c0\u67e5\u79c1\u94a5\u662f\u5426\u5c5e\u4e8e\u4e4b\u524d\u4e0b\u8f7d\u7684\u516c\u5171\u8bc1\u4e66\u7684\u6b65\u9aa4\u3002\u5982\u679cNextcloud\u5b9e\u4f8b\u63d0\u4f9b\u4e86\u4e00\u4e2a\u6076\u610f\u516c\u94a5\uff0c\u90a3\u4e48\u6570\u636e\u5c06\u4e3a\u6b64\u5bc6\u94a5\u8fdb\u884c\u52a0\u5bc6\uff0c\u4ece\u800c\u53ef\u4ee5\u88ab\u6076\u610f\u53c2\u4e0e\u8005\u8bbf\u95ee\u3002\u653b\u51fb\u8005\u53ef\u5229\u7528\u8be5\u6f0f\u6d1e\u83b7\u53d6\u654f\u611f\u4fe1\u606f\u3002",
  "formalWay": "\u76ee\u524d\u5382\u5546\u5df2\u53d1\u5e03\u5347\u7ea7\u8865\u4e01\u4ee5\u4fee\u590d\u6f0f\u6d1e\uff0c\u8865\u4e01\u83b7\u53d6\u94fe\u63a5\uff1a\r\nhttps://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736",
  "isEvent": "\u901a\u7528\u8f6f\u786c\u4ef6\u6f0f\u6d1e",
  "number": "CNVD-2021-51798",
  "openTime": "2021-07-19",
  "patchDescription": "Nextcloud\u662f\u5fb7\u56fdNextcloud\u516c\u53f8\u7684\u4e00\u5957\u5f00\u6e90\u7684\u81ea\u6258\u7ba1\u6587\u4ef6\u540c\u6b65\u548c\u5171\u4eab\u7684\u901a\u4fe1\u5e94\u7528\u5e73\u53f0\u3002\r\n\r\nNextcloud Android Client\u57283.16.1\u4e4b\u524d\u7248\u672c\u5b58\u5728\u4fe1\u4efb\u7ba1\u7406\u95ee\u9898\u6f0f\u6d1e\uff0c\u8be5\u6f0f\u6d1e\u6e90\u4e8eNextcloud Android\u5ba2\u6237\u7aef\u8df3\u8fc7\u4e86\u4e00\u4e2a\u6d89\u53ca\u5ba2\u6237\u7aef\u68c0\u67e5\u79c1\u94a5\u662f\u5426\u5c5e\u4e8e\u4e4b\u524d\u4e0b\u8f7d\u7684\u516c\u5171\u8bc1\u4e66\u7684\u6b65\u9aa4\u3002\u5982\u679cNextcloud\u5b9e\u4f8b\u63d0\u4f9b\u4e86\u4e00\u4e2a\u6076\u610f\u516c\u94a5\uff0c\u90a3\u4e48\u6570\u636e\u5c06\u4e3a\u6b64\u5bc6\u94a5\u8fdb\u884c\u52a0\u5bc6\uff0c\u4ece\u800c\u53ef\u4ee5\u88ab\u6076\u610f\u53c2\u4e0e\u8005\u8bbf\u95ee\u3002\u653b\u51fb\u8005\u53ef\u5229\u7528\u8be5\u6f0f\u6d1e\u83b7\u53d6\u654f\u611f\u4fe1\u606f\u3002\u76ee\u524d\uff0c\u4f9b\u5e94\u5546\u53d1\u5e03\u4e86\u5b89\u5168\u516c\u544a\u53ca\u76f8\u5173\u8865\u4e01\u4fe1\u606f\uff0c\u4fee\u590d\u4e86\u6b64\u6f0f\u6d1e\u3002",
  "patchName": "Nextcloud\u4fe1\u4efb\u7ba1\u7406\u95ee\u9898\u6f0f\u6d1e\uff08CNVD-2021-51798\uff09\u7684\u8865\u4e01",
  "products": {
    "product": "Nextcloud Nextcloud Android Client \u003c3.16.1"
  },
  "referenceLink": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736",
  "serverity": "\u4e2d",
  "submitTime": "2021-07-15",
  "title": "Nextcloud\u4fe1\u4efb\u7ba1\u7406\u95ee\u9898\u6f0f\u6d1e\uff08CNVD-2021-51798\uff09"
}

CVE-2021-32727 (GCVE-0-2021-32727)

Vulnerability from cvelistv5 – Published: 2021-07-12 20:40 – Updated: 2024-08-03 23:33

Title

End-to-end encryption device setup did not verify public key

Summary

Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account.

Severity

5.7 (Medium)


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

CWE

CWE-295 - Improper Certificate Validation

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/nextcloud/security-advisories/…	x_refsource_CONFIRM
https://github.com/nextcloud/android/pull/8438	x_refsource_MISC
https://hackerone.com/reports/1189162	x_refsource_MISC
https://github.com/nextcloud/end_to_end_encryptio…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
nextcloud	security-advisories	Affected: < 3.16.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T23:33:54.870Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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        "references": [
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/nextcloud/android/pull/8438"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://hackerone.com/reports/1189162"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "security-advisories",
          "vendor": "nextcloud",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.16.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.7,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-07-12T20:40:13.000Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nextcloud/android/pull/8438"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://hackerone.com/reports/1189162"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"
        }
      ],
      "source": {
        "advisory": "GHSA-5v33-r9cm-7736",
        "discovery": "UNKNOWN"
      },
      "title": "End-to-end encryption device setup did not verify public key",
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "security-advisories@github.com",
          "ID": "CVE-2021-32727",
          "STATE": "PUBLIC",
          "TITLE": "End-to-end encryption device setup did not verify public key"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "security-advisories",
                      "version": {
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                          {
                            "version_value": "\u003c 3.16.1"
                          }
                        ]
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        },
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            },
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  "cveMetadata": {
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    "cveId": "CVE-2021-32727",
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    "dateReserved": "2021-05-12T00:00:00.000Z",
    "dateUpdated": "2024-08-03T23:33:54.870Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

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.

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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.

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CNVD-2021-51798

CVE-2021-32727 (GCVE-0-2021-32727)

Tags

Sightings

Nomenclature

Related by attack behaviour