cvelistv5 - cve-2021-34473

CVE-2021-34473 (GCVE-0-2021-34473)

Vulnerability from cvelistv5

Published

2021-07-14 17:54

Modified

2025-10-21 23:25

Severity ?

9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C

CWE

Remote Code Execution

Summary

Microsoft Exchange Server Remote Code Execution Vulnerability

References

URL

Tags

	https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473	x_refsource_MISC
	https://www.zerodayinitiative.com/advisories/ZDI-21-821/	x_refsource_MISC
	http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html	x_refsource_MISC

Impacted products

Vendor

Product

Version

Microsoft

Microsoft Exchange Server 2013 Cumulative Update 23

Version: 15.00.0 < 15.00.1497.015
cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*

Microsoft	Microsoft Exchange Server 2019 Cumulative Update 9	Version: 15.02.0 < 15.02.0858.010 cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9::::::
Microsoft	Microsoft Exchange Server 2016 Cumulative Update 20	Version: 15.01.0 < 15.01.2242.008 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20::::::
Microsoft	Microsoft Exchange Server 2016 Cumulative Update 19	Version: 15.01.0 < 15.01.2176.012 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19::::::
Microsoft	Microsoft Exchange Server 2019 Cumulative Update 8	Version: 15.02.0 < 15.02.0792.013 cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8::::::

CISA Known Exploited Vulnerability

Data from the CISA Known Exploited Vulnerabilities Catalog

Date added: 2021-11-03

Due date: 2021-11-17

Required action: Apply updates per vendor instructions.

Used in ransomware: Known

Notes: https://nvd.nist.gov/vuln/detail/CVE-2021-34473

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T00:12:50.367Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-821/"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-34473",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-02-04T15:42:23.926450Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2021-11-03",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473"
              },
              "type": "kev"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-918",
                "description": "CWE-918 Server-Side Request Forgery (SSRF)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-21T23:25:40.913Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "government-resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2021-11-03T00:00:00.000Z",
            "value": "CVE-2021-34473 added to CISA KEV"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "cpes": [
            "cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*"
          ],
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Microsoft Exchange Server 2013 Cumulative Update 23",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.00.1497.015",
              "status": "affected",
              "version": "15.00.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*"
          ],
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Microsoft Exchange Server 2019 Cumulative Update 9",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.02.0858.010",
              "status": "affected",
              "version": "15.02.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*"
          ],
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Microsoft Exchange Server 2016 Cumulative Update 20",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.01.2242.008",
              "status": "affected",
              "version": "15.01.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*"
          ],
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Microsoft Exchange Server 2016 Cumulative Update 19",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.01.2176.012",
              "status": "affected",
              "version": "15.01.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*"
          ],
          "platforms": [
            "x64-based Systems"
          ],
          "product": "Microsoft Exchange Server 2019 Cumulative Update 8",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.02.0792.013",
              "status": "affected",
              "version": "15.02.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "datePublic": "2021-07-13T07:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "Microsoft Exchange Server Remote Code Execution Vulnerability"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "Remote Code Execution",
              "lang": "en-US",
              "type": "Impact"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2023-12-28T22:36:44.655Z",
        "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "shortName": "microsoft"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-821/"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html"
        }
      ],
      "title": "Microsoft Exchange Server Remote Code Execution Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
    "assignerShortName": "microsoft",
    "cveId": "CVE-2021-34473",
    "datePublished": "2021-07-14T17:54:03.000Z",
    "dateReserved": "2021-06-09T00:00:00.000Z",
    "dateUpdated": "2025-10-21T23:25:40.913Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "cisa_known_exploited": {
      "cveID": "CVE-2021-34473",
      "cwes": "[\"CWE-918\"]",
      "dateAdded": "2021-11-03",
      "dueDate": "2021-11-17",
      "knownRansomwareCampaignUse": "Known",
      "notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-34473",
      "product": "Exchange Server",
      "requiredAction": "Apply updates per vendor instructions.",
      "shortDescription": "Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution.",
      "vendorProject": "Microsoft",
      "vulnerabilityName": "Microsoft Exchange Server Remote Code Execution Vulnerability"
    }
  }
}

CERTFR-2021-AVI-522

Vulnerability from certfr_avis

De multiples vulnérabilités ont été corrigées dans les produits Microsoft. Elles permettent à un attaquant de provoquer une atteinte à la confidentialité des données, une usurpation d'identité, une exécution de code à distance, un contournement de la fonctionnalité de sécurité et une élévation de privilèges.

Solution

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

None

Impacted products

Vendor	Product	Description
Microsoft	N/A	Microsoft Exchange Server 2013 Cumulative Update 23
Microsoft	N/A	Microsoft Dynamics 365 Business Central 2021 Release Wave 1 - Update 18.3
Microsoft	N/A	Microsoft Exchange Server 2016 Cumulative Update 21
Microsoft	N/A	Microsoft Exchange Server 2016 Cumulative Update 19
Microsoft	N/A	HEVC Video Extensions
Microsoft	N/A	Microsoft Exchange Server 2019 Cumulative Update 8
Microsoft	N/A	Microsoft Malware Protection Engine
Microsoft	N/A	Power BI Report Server
Microsoft	N/A	Visual Studio Code
Microsoft	N/A	Microsoft 365 Apps pour Enterprise pour systèmes 32 bits
Microsoft	N/A	Microsoft 365 Apps pour Enterprise pour 64 bits Systems
Microsoft	N/A	Microsoft Exchange Server 2019 Cumulative Update 10
Microsoft	N/A	Microsoft Dynamics 365 Business Central 2020 Release Wave 1 - Update 16.14
Microsoft	N/A	Microsoft Exchange Server 2016 Cumulative Update 20
Microsoft	N/A	Microsoft Bing Search pour Android
Microsoft	N/A	Microsoft Exchange Server 2019 Cumulative Update 9
Microsoft	N/A	Microsoft Dynamics 365 Business Central 2020 Release Wave 2 - Update 17.8
Microsoft	N/A	Open Enclave SDK

References

Title

Publication Time

Tags

Bulletin de sécurité Microsoft du 14 juillet 2021

None

vendor-advisory

Show details on source website

JSON

To clipboard

{
  "$ref": "https://www.cert.ssi.gouv.fr/openapi.json",
  "affected_systems": [
    {
      "description": "Microsoft Exchange Server 2013 Cumulative Update 23",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Dynamics 365 Business Central 2021 Release Wave 1 - Update 18.3",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Exchange Server 2016 Cumulative Update 21",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Exchange Server 2016 Cumulative Update 19",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "HEVC Video Extensions",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Exchange Server 2019 Cumulative Update 8",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Malware Protection Engine",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Power BI Report Server",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Visual Studio Code",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft 365 Apps pour Enterprise pour syst\u00e8mes 32 bits",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft 365 Apps pour Enterprise pour 64 bits Systems",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Exchange Server 2019 Cumulative Update 10",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Dynamics 365 Business Central 2020 Release Wave 1 - Update 16.14",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Exchange Server 2016 Cumulative Update 20",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Bing Search pour Android",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Exchange Server 2019 Cumulative Update 9",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Microsoft Dynamics 365 Business Central 2020 Release Wave 2 - Update 17.8",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    },
    {
      "description": "Open Enclave SDK",
      "product": {
        "name": "N/A",
        "vendor": {
          "name": "Microsoft",
          "scada": false
        }
      }
    }
  ],
  "affected_systems_content": null,
  "content": "## Solution\n\nSe r\u00e9f\u00e9rer au bulletin de s\u00e9curit\u00e9 de l\u0027\u00e9diteur pour l\u0027obtention des\ncorrectifs (cf. section Documentation).\n",
  "cves": [
    {
      "name": "CVE-2021-31984",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-31984"
    },
    {
      "name": "CVE-2021-33777",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33777"
    },
    {
      "name": "CVE-2021-34470",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34470"
    },
    {
      "name": "CVE-2021-34528",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34528"
    },
    {
      "name": "CVE-2021-34501",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34501"
    },
    {
      "name": "CVE-2021-34464",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34464"
    },
    {
      "name": "CVE-2021-34522",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34522"
    },
    {
      "name": "CVE-2021-31947",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-31947"
    },
    {
      "name": "CVE-2021-34523",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34523"
    },
    {
      "name": "CVE-2021-34479",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34479"
    },
    {
      "name": "CVE-2021-33766",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33766"
    },
    {
      "name": "CVE-2021-34452",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34452"
    },
    {
      "name": "CVE-2021-33768",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33768"
    },
    {
      "name": "CVE-2021-33767",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33767"
    },
    {
      "name": "CVE-2021-33775",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33775"
    },
    {
      "name": "CVE-2021-33778",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33778"
    },
    {
      "name": "CVE-2021-31196",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-31196"
    },
    {
      "name": "CVE-2021-34469",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34469"
    },
    {
      "name": "CVE-2021-31206",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-31206"
    },
    {
      "name": "CVE-2021-33753",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33753"
    },
    {
      "name": "CVE-2021-33776",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33776"
    },
    {
      "name": "CVE-2021-34474",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34474"
    },
    {
      "name": "CVE-2021-34473",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34473"
    },
    {
      "name": "CVE-2021-34529",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34529"
    }
  ],
  "initial_release_date": "2021-07-15T00:00:00",
  "last_revision_date": "2021-07-15T00:00:00",
  "links": [],
  "reference": "CERTFR-2021-AVI-522",
  "revisions": [
    {
      "description": "Version initiale",
      "revision_date": "2021-07-15T00:00:00.000000"
    }
  ],
  "risks": [
    {
      "description": "Usurpation d\u0027identit\u00e9"
    },
    {
      "description": "Ex\u00e9cution de code arbitraire \u00e0 distance"
    },
    {
      "description": "Contournement de la fonctionnalit\u00e9 de s\u00e9curit\u00e9"
    },
    {
      "description": "Atteinte \u00e0 la confidentialit\u00e9 des donn\u00e9es"
    },
    {
      "description": "\u00c9l\u00e9vation de privil\u00e8ges"
    }
  ],
  "summary": "De multiples vuln\u00e9rabilit\u00e9s ont \u00e9t\u00e9 corrig\u00e9es dans \u003cspan\nclass=\"textit\"\u003eles produits Microsoft\u003c/span\u003e. Elles permettent \u00e0 un\nattaquant de provoquer une atteinte \u00e0 la confidentialit\u00e9 des donn\u00e9es,\nune usurpation d\u0027identit\u00e9, une ex\u00e9cution de code \u00e0 distance, un\ncontournement de la fonctionnalit\u00e9 de s\u00e9curit\u00e9 et une \u00e9l\u00e9vation de\nprivil\u00e8ges.\n",
  "title": "Multiples vuln\u00e9rabilit\u00e9s dans les produits Microsoft",
  "vendor_advisories": [
    {
      "published_at": null,
      "title": "Bulletin de s\u00e9curit\u00e9 Microsoft du 14 juillet 2021",
      "url": "https://msrc.microsoft.com/update-guide/"
    }
  ]
}

CERTFR-2021-ALE-017

Vulnerability from certfr_alerte

Dans son bulletin d'actualité CERTFR-2021-ACT-035 du 12 août 2021 [1], le CERT-FR revenait sur la publication d'une technique permettant de prendre le contrôle d'un serveur Microsoft Exchange. La technique, dénommée "ProxyShell" s'appuie sur l'existence de plusieurs vulnérabilités corrigées en avril et en mai 2021 [4] (mais annoncées en juillet) [2] [3].

Récemment, le CERT-FR a pris connaissance d'activités malveillantes qui pourraient-être basées sur une exploitation de ces vulnérabilités et ciblant les serveurs Microsoft Exchange d'entités françaises.

Le CERT-FR a signalé l'existence de serveurs vulnérables exposés sur Internet à leurs propriétaires, mais sans possibilité d'exhaustivité. Par conséquent le CERT-FR rappelle les recommandations suivantes :

appliquer immédiatement les correctifs de sécurité fournis par l’éditeur sur l’ensemble des serveurs Exchange vulnérables exposés sur Internet puis en interne ;
procéder à l’analyse des serveurs Exchange afin d’identifier une possible activité anormale à l'aide des informations fournies dans notre bulletin CERTFR-2021-ACT-035 et la présence de webshells ;
en cas de compromission, contrôler le système d’information pour détecter d’éventuelles latéralisations ainsi qu’une compromission des serveurs Active Directory.

Enfin, le CERT-FR rappelle que les serveurs Microsoft Exchange ne devraient pas être exposés sans protection sur Internet. Il est fortement recommandé d’appliquer les bonnes pratiques publiées par l’ANSSI pour ce type service [5].

Solution

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

Impacted products

	Vendor	Product	Description

References

Title

Publication Time

Tags

[2] Avis de sécurité CERTFR-2021-AVI-522 du 15 juillet 2021	-	other
[5] Guide de sécurité de l'ANSSI	-	other
[3] Bulletin d'actualité CERTFR-2021-ACT-030 du 19 juillet 2021	-	other
[1] Bulletin d'actualité CERTFR-2021-ACT-035 du 12 août 2021	-	other
[4] Avis de sécurité CERTFR-2021-AVI-369 du 12 mai 2021	-	other

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{
  "$ref": "https://www.cert.ssi.gouv.fr/openapi.json",
  "affected_systems": [],
  "affected_systems_content": "",
  "closed_at": "2022-05-04",
  "content": "## Solution\n\nSe r\u00e9f\u00e9rer au bulletin de s\u00e9curit\u00e9 de l\u0027\u00e9diteur pour l\u0027obtention des\ncorrectifs (cf. section Documentation).\n",
  "cves": [
    {
      "name": "CVE-2021-31207",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-31207"
    },
    {
      "name": "CVE-2021-34473",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34473"
    },
    {
      "name": "CVE-2021-34523",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-34523"
    }
  ],
  "initial_release_date": "2021-08-27T00:00:00",
  "last_revision_date": "2022-05-04T00:00:00",
  "links": [
    {
      "title": "[2] Avis de s\u00e9curit\u00e9\u00a0CERTFR-2021-AVI-522 du 15 juillet 2021",
      "url": "https://www.cert.ssi.gouv.fr/avis/CERTFR-2021-AVI-522/"
    },
    {
      "title": "[5] Guide de s\u00e9curit\u00e9 de l\u0027ANSSI",
      "url": "https://www.ssi.gouv.fr/guide/recommandations-sur-le-nomadisme-numerique/"
    },
    {
      "title": "[3] Bulletin d\u0027actualit\u00e9 CERTFR-2021-ACT-030 du 19 juillet 2021",
      "url": "https://www.cert.ssi.gouv.fr/actualite/CERTFR-2021-ACT-030/"
    },
    {
      "title": "[1] Bulletin d\u0027actualit\u00e9 CERTFR-2021-ACT-035 du 12 ao\u00fbt 2021",
      "url": "https://www.cert.ssi.gouv.fr/actualite/CERTFR-2021-ACT-035/"
    },
    {
      "title": "[4] Avis de s\u00e9curit\u00e9\u00a0CERTFR-2021-AVI-369 du 12 mai 2021",
      "url": "https://www.cert.ssi.gouv.fr/avis/CERTFR-2021-AVI-369/"
    }
  ],
  "reference": "CERTFR-2021-ALE-017",
  "revisions": [
    {
      "description": "Version initiale",
      "revision_date": "2021-08-27T00:00:00.000000"
    },
    {
      "description": "Cl\u00f4ture de l\u0027alerte. Cela ne signifie pas la fin d\u0027une menace. Seule l\u0027application de la mise \u00e0 jour permet de vous pr\u00e9munir contre l\u0027exploitation de la vuln\u00e9rabilit\u00e9 correspondante.",
      "revision_date": "2022-05-04T00:00:00.000000"
    }
  ],
  "risks": [
    {
      "description": "Ex\u00e9cution de code arbitraire \u00e0 distance"
    },
    {
      "description": "\u00c9l\u00e9vation de privil\u00e8ges"
    },
    {
      "description": "Contournement de la politique de s\u00e9curit\u00e9"
    }
  ],
  "summary": "Dans son bulletin d\u0027actualit\u00e9 CERTFR-2021-ACT-035 du 12 ao\u00fbt 2021\n[\\[1\\]](http://suite%20\u00e0%20la%20publication%20d\u0027une%20technique%20permettant%20de%20prendre%20le%20contr\u00f4le%20d\u0027un%20serveur%20Microsoft%20Exchange),\nle CERT-FR revenait sur la publication d\u0027une technique permettant de\nprendre le contr\u00f4le d\u0027un serveur Microsoft Exchange. La technique,\nd\u00e9nomm\u00e9e \"*ProxyShell*\" s\u0027appuie sur l\u0027existence de plusieurs\nvuln\u00e9rabilit\u00e9s corrig\u00e9es en avril et en mai 2021\n[\\[4\\]](/avis/CERTFR-2021-AVI-369/) (mais\nannonc\u00e9es en juillet)\n[\\[2\\]](/avis/CERTFR-2021-AVI-522/)\n[\\[3\\]](/actualite/CERTFR-2021-ACT-030/).\n\nR\u00e9cemment, le CERT-FR a pris connaissance d\u0027activit\u00e9s malveillantes qui\npourraient-\u00eatre bas\u00e9es sur une exploitation de ces vuln\u00e9rabilit\u00e9s et\nciblant les serveurs Microsoft Exchange d\u0027entit\u00e9s fran\u00e7aises.\n\nLe CERT-FR a signal\u00e9 l\u0027existence de serveurs vuln\u00e9rables expos\u00e9s sur\nInternet \u00e0 leurs propri\u00e9taires, mais sans possibilit\u00e9 d\u0027exhaustivit\u00e9.\nPar cons\u00e9quent le CERT-FR rappelle les recommandations suivantes :\n\n-   appliquer imm\u00e9diatement les correctifs de s\u00e9curit\u00e9 fournis par\n    l\u2019\u00e9diteur sur l\u2019ensemble des serveurs Exchange vuln\u00e9rables expos\u00e9s\n    sur Internet puis en interne ;\n-   proc\u00e9der \u00e0 l\u2019analyse des serveurs Exchange afin d\u2019identifier une\n    possible activit\u00e9 anormale \u00e0 l\u0027aide des informations fournies dans\n    notre bulletin CERTFR-2021-ACT-035 et la pr\u00e9sence de *webshells* ;\n-   en cas de compromission, contr\u00f4ler le syst\u00e8me d\u2019information pour\n    d\u00e9tecter d\u2019\u00e9ventuelles lat\u00e9ralisations ainsi qu\u2019une compromission\n    des serveurs Active Directory.\n\nEnfin, le CERT-FR rappelle que les serveurs Microsoft Exchange ne\ndevraient pas \u00eatre expos\u00e9s sans protection sur Internet. Il est\nfortement recommand\u00e9 d\u2019appliquer les bonnes pratiques publi\u00e9es par\nl\u2019ANSSI pour ce type service\n[\\[5\\]](https://www.ssi.gouv.fr/guide/recommandations-sur-le-nomadisme-numerique/).\n",
  "title": "Multiples vuln\u00e9rabilit\u00e9s dans Microsoft Exchange",
  "vendor_advisories": []
}

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Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
Confirmed: The vulnerability is confirmed from an analyst perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
Patched: This vulnerability was successfully patched by the user reporting the sighting.
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Not confirmed: The user expresses doubt about the veracity of the vulnerability.
Not patched: This vulnerability was not successfully patched by the user reporting the sighting.

Action not permitted

CVE-2021-34473 (GCVE-0-2021-34473)

Vulnerability from cvelistv5

CISA Known Exploited Vulnerability

Data from the CISA Known Exploited Vulnerabilities Catalog

CERTFR-2021-AVI-522

Vulnerability from certfr_avis

Solution

CERTFR-2021-ALE-017

Vulnerability from certfr_alerte

Solution

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