{"id":"CVE-2018-11518","aliases":["EUVD-2018-3547","GHSA-vv3x-8gqc-m4c5"],"status":"published","title":"A vulnerability allows a phreaking attack on HCL legacy IVR systems that do not use VoIP. These...","description":"A vulnerability allows a phreaking attack on HCL legacy IVR 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 for service activations. This is a request-forgery issue when the required series of DTMF signals for a service activation is predictable (e.g., the IVR system does not speak a nonce to the caller). In this case, the IVR system accepts an activation request from a less-secure channel (any loudspeaker in the caller's physical environment) without verifying that the request was intended (it matches a nonce sent over a more-secure channel to the caller's earpiece).","severity":{"version":"3.0","score":8.1,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.01371,"percentile":0.72125,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-20"],"published":"2018-05-30T20:00:00Z","modified":"2026-06-17T01:36:05Z","products":[{"vendor":"hcltech","product":"legacy_ivr_firmware"}],"references":[{"url":"https://twitter.com/mishradhiraj_/status/1001664440759091207","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://datarift.blogspot.com/2018/05/CVE-2018-11518-abusing-ivr-systems.html","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"http://virgil-cj.blogspot.com/2018/05/0day-legacy-ivr-lets-phreak.html","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://twitter.com/mishradhiraj_/status/1001664204485652482","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-11518"},{"url":"https://github.com/advisories/GHSA-vv3x-8gqc-m4c5"}],"sources":{"cve":[{"id":"CVE-2018-11518","description":"A vulnerability allows a phreaking attack on HCL legacy IVR 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 for service activations. This is a request-forgery issue when the required series of DTMF signals for a service activation is predictable (e.g., the IVR system does not speak a nonce to the caller). In this case, the IVR system accepts an activation request from a less-secure channel (any loudspeaker in the caller's physical environment) without verifying that the request was intended (it matches a nonce sent over a more-secure channel to the caller's earpiece).","status":"published","published":"2018-05-30T20:00:00Z","modified":"2024-08-05T08:10:14.61Z","updated_at":"2026-11-02T14:35:09.908186Z"}],"euvd":[{"id":"EUVD-2018-3547","description":"A vulnerability allows a phreaking attack on HCL legacy IVR 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 for service activations. This is a request-forgery issue when the required series of DTMF signals for a service activation is predictable (e.g., the IVR system does not speak a nonce to the caller). In this case, the IVR system accepts an activation request from a less-secure channel (any loudspeaker in the caller's physical environment) without verifying that the request was intended (it matches a nonce sent over a more-secure channel to the caller's earpiece).","status":"published","published":"2018-05-30T20:00:00Z","modified":"2024-08-05T08:10:14Z","updated_at":"2026-11-03T02:39:54.984528Z"}],"ghsa":[{"id":"GHSA-vv3x-8gqc-m4c5","title":"A vulnerability allows a phreaking attack on HCL legacy IVR systems that do not use VoIP. These...","description":"A vulnerability allows a phreaking attack on HCL legacy IVR 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 for service activations. This is a request-forgery issue when the required series of DTMF signals for a service activation is predictable (e.g., the IVR system does not speak a nonce to the caller). In this case, the IVR system accepts an activation request from a less-secure channel (any loudspeaker in the caller's physical environment) without verifying that the request was intended (it matches a nonce sent over a more-secure channel to the caller's earpiece).","status":"published","published":"2022-05-14T03:12:34Z","modified":"2023-02-02T05:07:27Z","cvss":[{"version":"3.0","score":8.1,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:52:30.631112Z"}],"nvd":[{"id":"CVE-2018-11518","description":"A vulnerability allows a phreaking attack on HCL legacy IVR 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 for service activations. This is a request-forgery issue when the required series of DTMF signals for a service activation is predictable (e.g., the IVR system does not speak a nonce to the caller). In this case, the IVR system accepts an activation request from a less-secure channel (any loudspeaker in the caller's physical environment) without verifying that the request was intended (it matches a nonce sent over a more-secure channel to the caller's earpiece).","status":"published","published":"2018-05-30T20:29:00.25Z","modified":"2026-06-17T01:36:05.96Z","cvss":[{"version":"3.0","score":8.1,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:04:28.483469Z"}]}}