CVE-2017-17704
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 door-unlocking issue was discovered on Software House iStar Ultra devices through 6.5.2.20569 when used in conjunction with the IP-ACM Ethernet Door Module. The communications between the IP-ACM and the iStar Ultra is encrypted using a fixed AES key and IV. Each message is encrypted in CBC mode and restarts with the fixed IV, leading to replay attacks of entire messages. There is no authentication of messages beyond the use of the fixed AES key, so message forgery is also possible.
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 confidenceSoftware House iStar Ultra devices (up to 6.5.2.20569) paired with IP-ACM Ethernet Door Modules use a hardcoded fixed AES key and IV for encrypting communications in CBC mode. Since each message restarts with the same fixed IV and there is no message authentication, attackers can capture and replay previously captured messages to unlock doors, or forge new messages using the known encryption parameters.
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 data<= 6.5.2.20569CVSS 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
- None
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/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 iStar Ultra firmware versionAccess the iStar Ultra device administrative interface or check the device firmware version through its management console. The firmware version is typically displayed in the system information or About section of the device web UI or CLI.Affected if The installed firmware version is 6.5.2.20569 or lower.
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Confirm IP-ACM module deploymentInventory network devices to determine if IP-ACM Ethernet Door Modules are connected to or paired with the iStar Ultra controller. Check the physical network topology or the door controller's device list.Affected if IP-ACM Ethernet Door Modules are present and connected to the iStar Ultra device.
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Verify door controller communication encryptionInspect network traffic between the iStar Ultra and IP-ACM modules using a packet capture tool. Look for encrypted communications and identify whether the same cryptographic parameters appear across multiple captured packets.Affected if Communications use AES encryption with a fixed repeating IV and no message authentication is present.
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Review door controller for hardcoded credentialsCheck the iStar Ultra configuration files or firmware image for hardcoded AES keys. This may require access to backup configurations or firmware analysis tools.Affected if A hardcoded fixed AES key is found in the device configuration or firmware.
You are affected if your iStar Ultra firmware is version 6.5.2.20569 or lower and IP-ACM Ethernet Door Modules are connected, with communications using hardcoded fixed AES encryption and no message authentication.
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 dataContact Software House for firmware updates that implement unique per-message IVs and message authentication codes (MAC). If no update is available, consider network segmentation to restrict physical access to the door controller communication lines.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA8.0 h
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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-2017-17704 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
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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