DBLTek GoIP 2016 Telnet Administrative Interface inclusion of undocumented features or chicken bits

Summaryinfo

A vulnerability classified as very critical has been found in DBLTek GoIP 2016. This issue affects some unknown processing of the component Telnet Administrative Interface. The manipulation leads to inclusion of undocumented features or chicken bits. This vulnerability is uniquely identified as CVE-2017-20204. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in DBLTek GoIP 2016. It has been rated as very critical. This issue affects some unknown processing of the component Telnet Administrative Interface. The manipulation with an unknown input leads to a inclusion of undocumented features or chicken bits vulnerability. Using CWE to declare the problem leads to CWE-1242. The device includes chicken bits or undocumented features that can create entry points for unauthorized actors. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

DBLTek GoIP devices (models GoIP 1, 4, 8, 16, and 32) contain an undocumented vendor backdoor in the Telnet administrative interface that allows remote authentication as an undocumented user via a proprietary challenge–response scheme which is fundamentally flawed. Because the challenge response can be computed from the challenge itself, a remote attacker can authenticate without knowledge of a secret and obtain a root shell on the device. This can lead to persistent remote code execution, full device compromise, and arbitrary control of the device and any managed services. The firmware used within these devices was updated in December 2016 to make this vulnerability more complex to exploit. However, it is unknown if DBLTek has taken steps to fully mitigate.

The identification of this vulnerability is CVE-2017-20204 since 10/14/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/17/2025).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at CNNVD (CNNVD-202510-2275) and EUVD (EUVD-2017-18921). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• DBLTek

Name

• GoIP

Version

• 2016

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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CVSSv3info

CVSSv2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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