CVE-2017-11436
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 · uneditedD-Link DIR-615 before v20.12PTb04 has a second admin account with a 0x1 BACKDOOR value, which might allow remote attackers to obtain access via a TELNET connection.
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 confidenceThe D-Link DIR-615 router firmware before version 20.12PTb04 contains a hardcoded backdoor admin account with a special 0x1 BACKDOOR flag value. This hidden account is accessible via remote TELNET connections, allowing unauthenticated attackers to gain full administrative control over the device.
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<= 20.12ptb01CVSS 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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/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 device modelAccess the router web interface or check the device label to confirm it is a D-Link DIR-615 modelAffected if The device is not a D-Link DIR-615 router
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Check the firmware versionLog into the router web interface and navigate to the Status or System Information page to view the firmware version. Compare it against the affected range: any version 20.12ptb01 or earlier.Affected if The firmware version is 20.12ptb01 or lower (older than 20.12PTb04)
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Verify if TELNET remote access is enabledAccess the router web interface and check the Remote Management settings or Security settings for TELNET/port 23 access configuration. Alternatively, attempt a telnet connection to the router's public IP on port 23 from an external network.Affected if TELNET access is enabled and accessible remotely (port 23 open)
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Test for the backdoor accountConnect to the router via TELNET (if enabled) and attempt to log in with the hardcoded backdoor credentials. The vulnerability description indicates a hidden admin account exists with a special 0x1 BACKDOOR flag value.Affected if A login succeeds using a hidden or undocumented admin account that provides full administrative access
You are affected if you have a D-Link DIR-615 router running firmware version 20.12ptb01 or earlier with TELNET remote access enabled, as this allows unauthenticated attackers to access the hardcoded backdoor admin account.
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.
dbcve · scopedUpgrade the D-Link DIR-615 firmware to version 20.12PTb04 or later to remove the hardcoded backdoor account. As an interim measure, disable TELNET access on the device and monitor for unauthorized remote access attempts.
v20.12PTb04 or later
- Obtain the firmware version v20.12PTb04 or later from the official D-Link support website (ftp2.dlink.com or dlink.com)
- Navigate to the device administration web interface
- Locate the Firmware Upgrade or System section
- Upload and apply the updated firmware file
- After the device restarts, verify the firmware version has been updated
- Disable TELNET access through the router configuration if not needed
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-11436 — 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-2017-11436 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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