{"cve":"CVE-2018-11518","nvd":{"published":"2018-05-30T20:29:00.250","modified":"2026-06-17T01:36:05.960","status":"Modified","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).","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-20"],"references":["http://virgil-cj.blogspot.com/2018/05/0day-legacy-ivr-lets-phreak.html","https://datarift.blogspot.com/2018/05/CVE-2018-11518-abusing-ivr-systems.html","https://twitter.com/mishradhiraj_/status/1001664204485652482","https://twitter.com/mishradhiraj_/status/1001664440759091207","http://virgil-cj.blogspot.com/2018/05/0day-legacy-ivr-lets-phreak.html"],"products":["hcltech:legacy_ivr_firmware"],"source":"nvd","synced_at":"2026-10-19T20:50:40.212176939+00:00"},"epss":{"cve":"CVE-2018-11518","score":0.01398,"percentile":0.72441,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}