Vulnerability-Lookup

CNVD-2021-34514

Vulnerability from cnvd - Published: 2021-05-14

Title

Exim后置链接漏洞

Description

Exim是一个运行于Unix系统中的开源消息传送代理（MTA），它主要负责邮件的路由、转发和投递。 Exim 存在安全漏洞，该漏洞源于Exim日志目录中的符号链接以下问题而存在的。攻击者可利用该漏洞覆盖文件系统上任何位置的关键root所有文件。

Severity

高

Patch Name

Exim后置链接漏洞的补丁

Patch Description

Exim是一个运行于Unix系统中的开源消息传送代理（MTA），它主要负责邮件的路由、转发和投递。 Exim 存在安全漏洞，该漏洞源于Exim日志目录中的符号链接以下问题而存在的。攻击者可利用该漏洞覆盖文件系统上任何位置的关键root所有文件。目前，供应商发布了安全公告及相关补丁信息，修复了此漏洞。

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://www.debian.org/security/2021/dsa-4912

Reference

https://nvd.nist.gov/vuln/detail/CVE-2020-28007

Impacted products

Name
Exim Exim >=4.00，<4.94.2

Show details on source website

JSON

To clipboard

{
  "cves": {
    "cve": {
      "cveNumber": "CVE-2020-28007"
    }
  },
  "description": "Exim\u662f\u4e00\u4e2a\u8fd0\u884c\u4e8eUnix\u7cfb\u7edf\u4e2d\u7684\u5f00\u6e90\u6d88\u606f\u4f20\u9001\u4ee3\u7406\uff08MTA\uff09\uff0c\u5b83\u4e3b\u8981\u8d1f\u8d23\u90ae\u4ef6\u7684\u8def\u7531\u3001\u8f6c\u53d1\u548c\u6295\u9012\u3002\n\nExim \u5b58\u5728\u5b89\u5168\u6f0f\u6d1e\uff0c\u8be5\u6f0f\u6d1e\u6e90\u4e8eExim\u65e5\u5fd7\u76ee\u5f55\u4e2d\u7684\u7b26\u53f7\u94fe\u63a5\u4ee5\u4e0b\u95ee\u9898\u800c\u5b58\u5728\u7684\u3002\u653b\u51fb\u8005\u53ef\u5229\u7528\u8be5\u6f0f\u6d1e\u8986\u76d6\u6587\u4ef6\u7cfb\u7edf\u4e0a\u4efb\u4f55\u4f4d\u7f6e\u7684\u5173\u952eroot\u6240\u6709\u6587\u4ef6\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://www.debian.org/security/2021/dsa-4912",
  "isEvent": "\u901a\u7528\u8f6f\u786c\u4ef6\u6f0f\u6d1e",
  "number": "CNVD-2021-34514",
  "openTime": "2021-05-14",
  "patchDescription": "Exim\u662f\u4e00\u4e2a\u8fd0\u884c\u4e8eUnix\u7cfb\u7edf\u4e2d\u7684\u5f00\u6e90\u6d88\u606f\u4f20\u9001\u4ee3\u7406\uff08MTA\uff09\uff0c\u5b83\u4e3b\u8981\u8d1f\u8d23\u90ae\u4ef6\u7684\u8def\u7531\u3001\u8f6c\u53d1\u548c\u6295\u9012\u3002\r\n\r\nExim \u5b58\u5728\u5b89\u5168\u6f0f\u6d1e\uff0c\u8be5\u6f0f\u6d1e\u6e90\u4e8eExim\u65e5\u5fd7\u76ee\u5f55\u4e2d\u7684\u7b26\u53f7\u94fe\u63a5\u4ee5\u4e0b\u95ee\u9898\u800c\u5b58\u5728\u7684\u3002\u653b\u51fb\u8005\u53ef\u5229\u7528\u8be5\u6f0f\u6d1e\u8986\u76d6\u6587\u4ef6\u7cfb\u7edf\u4e0a\u4efb\u4f55\u4f4d\u7f6e\u7684\u5173\u952eroot\u6240\u6709\u6587\u4ef6\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": "Exim\u540e\u7f6e\u94fe\u63a5\u6f0f\u6d1e \u7684\u8865\u4e01",
  "products": {
    "product": "Exim Exim \u003e=4.00\uff0c\u003c4.94.2"
  },
  "referenceLink": "https://nvd.nist.gov/vuln/detail/CVE-2020-28007",
  "serverity": "\u9ad8",
  "submitTime": "2021-05-14",
  "title": "Exim\u540e\u7f6e\u94fe\u63a5\u6f0f\u6d1e"
}

CVE-2020-28007 (GCVE-0-2020-28007)

Vulnerability from cvelistv5 – Published: 2021-05-06 02:58 – Updated: 2024-08-04 16:25

Summary

Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. Because Exim operates as root in the log directory (owned by a non-root user), a symlink or hard link attack allows overwriting critical root-owned files anywhere on the filesystem.

Severity

No CVSS data available.

CWE

Assigner

mitre mitre root

References

1 reference

URL	Tags
https://www.exim.org/static/doc/security/CVE-2020…	x_refsource_MISC

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T16:25:44.122Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28007-LFDIR.txt"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. Because Exim operates as root in the log directory (owned by a non-root user), a symlink or hard link attack allows overwriting critical root-owned files anywhere on the filesystem."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-05-06T02:58:36.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28007-LFDIR.txt"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2020-28007",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "n/a",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "n/a"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "n/a"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. Because Exim operates as root in the log directory (owned by a non-root user), a symlink or hard link attack allows overwriting critical root-owned files anywhere on the filesystem."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "n/a"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28007-LFDIR.txt",
              "refsource": "MISC",
              "url": "https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28007-LFDIR.txt"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2020-28007",
    "datePublished": "2021-05-06T02:58:36.000Z",
    "dateReserved": "2020-10-30T00:00:00.000Z",
    "dateUpdated": "2024-08-04T16:25:44.122Z",
    "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.

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.

Action not permitted

CNVD-2021-34514

CVE-2020-28007 (GCVE-0-2020-28007)

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