A method may include receiving an attach request that includes an international mobile equipment identity (IMEI) and an international mobile subscriber identity (IMSI), and determining whether the IMEI is associated with a user device that is not allowed to attach to the network. The method may also include determining whether the IMSI included in the attach request is stored in a database, and determining whether an IMEI associated with the IMSI is stored in the database. The method may further include determining whether the IMEI stored in the database matches the IMEI included in the attach request and denying the attach request in response to determining that the IMEI stored in the database does not match the IMEI included in the attach request.