A vulnerability tracked as CVE-2018-11518 could be exploited by attackers to power a phreaking attack on HCL legacy Interactive Voice Response systems that do not use VoIP. These IVR systems rely on various frequencies of audio signals; based on the frequency, certain commands and functions are processed. Since these frequencies are accepted within a phone call, an attacker can record these frequencies and use them to activate services or to get sensitive information for one or multiple users at the same time.”]