CVE-2021-30116 : Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on pr

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&pw=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.

Published 2021-07-09 14:15:08

Updated 2023-10-23 14:15:09

Source MITRE

View at NVD, CVE.org

CVE-2021-30116 is in the CISA Known Exploited Vulnerabilities Catalog

This issue is known to have been leveraged as part of a ransomware campaign.

CISA vulnerability name:

Kaseya Virtual System/Server Administrator (VSA) Information Disclosure Vulnerability

CISA required action:

Apply updates per vendor instructions.

CISA 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.

Added on 2021-11-03 Action due date 2021-11-17

Exploit prediction scoring system (EPSS) score for CVE-2021-30116

Probability of exploitation activity in the next 30 days: 88.54%

Percentile, the proportion of vulnerabilities that are scored at or less: ~ 99 % EPSS Score History EPSS FAQ

CVSS scores for CVE-2021-30116

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
7.5	HIGH	AV:N/AC:L/Au:N/C:P/I:P/A:P	10.0	6.4	NIST
Access Vector: Network Access Complexity: Low Authentication: None Confidentiality Impact: Partial Integrity Impact: Partial Availability Impact: Partial
10.0	CRITICAL	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H	3.9	6.0	MITRE
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Changed Confidentiality: High Integrity: High Availability: High
9.8	CRITICAL	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	3.9	5.9	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Unchanged Confidentiality: High Integrity: High Availability: High

CWE ids for CVE-2021-30116

CWE-522 Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2021-30116

https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil/

Kaseya VSA REvil Ransomware Attack 2021.
https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2/

Kaseya Case Update 2 | DIVD CSIRT
Third Party Advisory
https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/

Kaseya VSA Limited Disclosure | DIVD CSIRT
Third Party Advisory

CVEs referencing this url
https://helpdesk.kaseya.com/hc/en-gb/articles/4403440684689-Important-Notice-July-2nd-2021

Important Notice July 9th, 2021 – Kaseya
Vendor Advisory

Products affected by CVE-2021-30116