CVE Vulnerabilities

CVE-2021-27786

Permissive Cross-domain Policy with Untrusted Domains

Published: Jun 09, 2022 | Modified: Nov 21, 2024
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
6.8 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

Cross-origin resource sharing (CORS) enables browsers to perform cross domain requests in a controlled manner. This request has an Origin header that identifies the domain that is making the initial request and defines the protocol between a browser and server to see if the request is allowed. An attacker can take advantage of this and possibly carry out privileged actions and access sensitive information when the Access-Control-Allow-Credentials is enabled.

Weakness

The product uses a cross-domain policy file that includes domains that should not be trusted.

Affected Software

Name Vendor Start Version End Version
Onetest_server Hcltech 10.0 (including) 10.0 (including)
Onetest_server Hcltech 10.1 (including) 10.1 (including)
Onetest_server Hcltech 10.2 (including) 10.2 (including)

Extended Description

A cross-domain policy file (“crossdomain.xml” in Flash and “clientaccesspolicy.xml” in Silverlight) defines a list of domains from which a server is allowed to make cross-domain requests. When making a cross-domain request, the Flash or Silverlight client will first look for the policy file on the target server. If it is found, and the domain hosting the application is explicitly allowed to make requests, the request is made. Therefore, if a cross-domain policy file includes domains that should not be trusted, such as when using wildcards, then the application could be attacked by these untrusted domains. An overly permissive policy file allows many of the same attacks seen in Cross-Site Scripting (CWE-79). Once the user has executed a malicious Flash or Silverlight application, they are vulnerable to a variety of attacks. The attacker could transfer private information, such as cookies that may include session information, from the victim’s machine to the attacker. The attacker could send malicious requests to a web site on behalf of the victim, which could be especially dangerous to the site if the victim has administrator privileges to manage that site. In many cases, the attack can be launched without the victim even being aware of it.

Potential Mitigations

References