{"id":"CVE-2021-30116","aliases":["EUVD-2021-17056","GHSA-qm28-hjhx-pwqg"],"status":"published","title":"Unauthenticated credential leak and business logic flaw in Kaseya VSA \u003c= v9.5.6","description":"Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\\Program Files (x86)\\Kaseya\\XXXXXXXXXX\\KaseyaD.ini) which contains an Agent_Guid and AgentPassword This Agent_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813\u0026pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- * Unauthenticated download page leaks credentials * Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents * dl.asp accepts credentials via a GET request * Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.","severity":{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.85735,"percentile":0.9973,"model":"v2026.06.15"},"facts":{"in_kev":true,"known_exploited":true,"public_exploit":false,"fix_available":false},"cwes":["CWE-522"],"published":"2021-07-09T00:00:00Z","modified":"2026-08-14T05:16:54Z","kev":{"date_added":"2021-11-03","due_date":"2021-11-17","required_action":"Apply updates per vendor instructions.","known_ransomware_use":"Known"},"exploitation":[{"source":"euvd","since":"2021-11-03"},{"source":"kev","since":"2021-11-03"}],"exploits":[{"source":"nuclei","id":"CVE-2021-30116","title":"Kaseya VSA \u003c 9.5.7 - Credential Disclosure via Windows Agent","type":"detection template","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-30116.yaml"}],"products":[{"vendor":"kaseya","product":"virtual system/server administrator (vsa)"},{"vendor":"kaseya","product":"vsa_agent"},{"vendor":"kaseya","product":"vsa_server"}],"references":[{"url":"https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2/","tags":["x_transferred","Third Party Advisory"]},{"url":"https://helpdesk.kaseya.com/hc/en-gb/articles/4403440684689-Important-Notice-July-2nd-2021","tags":["x_transferred","Vendor Advisory"]},{"url":"https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/","tags":["x_transferred","Third Party Advisory"]},{"url":"https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil/","tags":["x_transferred","Exploit","Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30116","tags":["government-resource","US Government Resource"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-30116"},{"url":"https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2"},{"url":"https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure"},{"url":"https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil"},{"url":"https://github.com/advisories/GHSA-qm28-hjhx-pwqg"}],"sources":{"cve":[{"id":"CVE-2021-30116","title":"Unauthenticated credential leak and business logic flaw in Kaseya VSA \u003c= v9.5.6","description":"Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\\Program Files (x86)\\Kaseya\\XXXXXXXXXX\\KaseyaD.ini) which contains an Agent_Guid and AgentPassword This Agent_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813\u0026pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- * Unauthenticated download page leaks credentials * Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents * dl.asp accepts credentials via a GET request * Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.","status":"published","published":"2021-07-09T00:00:00Z","modified":"2026-08-14T03:55:30.74Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T14:33:01.852999Z"}],"euvd":[{"id":"EUVD-2021-17056","description":"Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\\Program Files (x86)\\Kaseya\\XXXXXXXXXX\\KaseyaD.ini) which contains an Agent_Guid and AgentPassword This Agent_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813\u0026pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- * Unauthenticated download page leaks credentials * Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents * dl.asp accepts credentials via a GET request * Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.","status":"published","published":"2021-07-09T00:00:00Z","modified":"2026-08-14T03:55:30Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"exploited_since":"2021-11-03","updated_at":"2026-11-02T18:01:55.248337Z"}],"ghsa":[{"id":"GHSA-qm28-hjhx-pwqg","title":"Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021.","description":"Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021.","status":"published","published":"2022-05-24T19:07:22Z","modified":"2025-10-22T00:33:22Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T15:04:08.198655Z"}],"kev":[{"id":"CVE-2021-30116","title":"Kaseya Virtual System/Server Administrator (VSA) Information Disclosure Vulnerability","description":"Kaseya Virtual System/Server Administrator (VSA) contains an information disclosure vulnerability allowing an attacker to obtain the sessionId that can be used to execute further attacks against the system.","cwes":["CWE-522"],"kev":{"date_added":"2021-11-03","due_date":"2021-11-17","required_action":"Apply updates per vendor instructions.","known_ransomware_use":"Known"},"updated_at":"2026-11-02T17:00:17.050017Z"}],"nvd":[{"id":"CVE-2021-30116","description":"Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\\Program Files (x86)\\Kaseya\\XXXXXXXXXX\\KaseyaD.ini) which contains an Agent_Guid and AgentPassword This Agent_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813\u0026pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- * Unauthenticated download page leaks credentials * Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents * dl.asp accepts credentials via a GET request * Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.","status":"published","published":"2021-07-09T14:15:07.77Z","modified":"2026-08-14T05:16:54.497Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T14:06:55.259633Z"}]}}