CVE-2023-0242

Rapid7 Velociraptor allows users to be created with different privileges on the server. Administrators are generally allowed to run any command on the server including writing arbitrary files. However, lower privilege users are generally forbidden from writing or modifying files on the server.

The VQL copy() function applies permission checks for reading files but does not check for permission to write files. This allows a low privilege user (usually, users with the Velociraptor investigator role) to overwrite files on the server, including Velociraptor configuration files.

To exploit this vulnerability, the attacker must already have a Velociraptor user account at a low privilege level (at least analyst) and be able to log into the GUI and create a notebook where they can run the VQL query invoking the copy() VQL function. Typically, most users deploy Velociraptor with limited access to a trusted group (most users will be administrators within the GUI). This vulnerability is associated with program files https://github.Com/Velocidex/velociraptor/blob/master/vql/filesystem/copy.go https://github.Com/Velocidex/velociraptor/blob/master/vql/filesystem/copy.go and program routines copy().

This issue affects Velociraptor versions before 0.6.7-5. Version 0.6.7-5, released January 16, 2023, fixes the issue.

Weakness

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Affected Software

Extended Description

Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user’s privileges and any permissions or other access-control specifications that apply to the resource. When access control checks are not applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.

Potential Mitigations

• Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.
• Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
• For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
• One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/665.html

References

• https://docs.velociraptor.app/announcements/2023-cves/#:~:text=to%20upgrade%20clients.-,CVE%2D2023%2D0242,-Insufficient%20Permission%20Check