CVE-2018-11518
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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).
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThis vulnerability in HCL legacy IVR systems allows a phreaking attack where an attacker exploits the system's reliance on predictable DTMF frequency signals for service activation. The IVR accepts activation commands from any audio source (e.g., a loudspeaker in the caller's environment) without verifying the request originated from the caller's earpiece, because the system does not use a nonce or challenge-response mechanism to confirm caller intent.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the IVR systemConfirm the deployed IVR system is HCL Legacy IVR by checking system documentation, firmware banners, or administrative interfacesAffected if The system is confirmed to be HCL Legacy IVR Firmware (all versions are affected)
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Verify DTMF command acceptancePlace a test call to the IVR and attempt to trigger service activation commands using DTMF tones played from an external speaker or audio file (not from the handset)Affected if The IVR accepts and acts on DTMF commands that originate from the call audio path rather than requiring input directly from the caller device
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Check for caller audio source verificationDuring a test call, inject audio commands via a second audio source (loudspeaker) while the caller line is open and observe whether the system processes those commandsAffected if The IVR processes commands from any audio source on the call without verifying the signal originated from the caller's earpiece
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Confirm absence of challenge-response mechanismInitiate a service activation request through the IVR and observe whether the system issues a unique nonce or challenge value that must be echoed back by the callerAffected if The IVR processes activation commands without generating and validating a nonce or challenge-response pair to confirm caller intent through the secure channel
If the system is HCL Legacy IVR Firmware and processes DTMF or voice commands without verifying they originate from the caller's handset or without using a nonce challenge-response mechanism, it is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement a nonce-based challenge-response mechanism where the IVR generates a unique value, speaks it to the caller's earpiece, and requires the caller to echo it back to confirm the request was intentionally initiated from the secure channel.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2018-11518 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-11518 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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