Backdoors Discovered Within Auerswald VoIP
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- By David Lukic
- Published: Dec 27, 2021
- Last Updated: Mar 18, 2022
Digital security specialists have found hidden backdoors within Auerswald VoIP systems. Made in Germany, these systems are intended to provide a secure means of engaging in voice calls. The hidden backdoors have the potential to be abused to provide criminals with access to VoIP devices.
How Were the Backdoors Discovered?
RedTeam Pentesting states it found the backdoors after performing a deeper dive into Auerswald services for regaining access to administrator accounts. The password tied to the privileged account is reset with an outreach to the manufacturer. The problem is that digital miscreants merely need the password for the Schandelah username to gain access to the PBX serial number. The serial number can be obtained, using an unauthenticated endpoint, setting the stage for the digital criminal to obtain access to an online interface.
The administrator password is reset after the interface is accessed. The backdoor allows hackers to tap into the PBX with unrestrained access. The end result is a full compromising of the VoIP device.
The RedTeam Pentesting team also pinpointed another backdoor accessible with the “admin” username. A fallback password is used with an algorithm, yet there is no need to alter the password to obtain complete PBX access.
Why are the Backdoors a Problem?
The Auerswald VoIP backdoors are an issue as digital security professionals cannot disable them. One of the backdoors allows access to the “admin” user with the highest possible privileges. The second backdoor password is applicable to a secret unnamed user referred to with the pseudonym of Schandelah. The vulnerability is referred to as CVE-2021-40859. This vulnerability has a 9.8 critical severity rating.
What Else is Known About Schandelah?
The researchers who analyzed the VoIP secret backdoors found these web-based devices for voice interaction were configured to find the Schandelah username. This is a hard-coded username. The devices searched for Schandelah in addition to sub-admin, which the account requires for device management.
Schandelah might ring a bell with those who’ve traveled to Germany as it is the name of a small village in the northern part of the country. Schandelah is the town where Auerswald manufactures its VoIP devices.
What Role Does PBX Play in the VoIP Backdoors?
PBX is an acronym that stands for private branch exchange. This switching system creates and manages voice calls between endpoints within telecommunication systems. PBX is a component of customary phone sets, devices on VoIP networks, and public phone networks. RedTeam Pentesting found the password for the Schandelah moniker is obtained by concatenating the serial number of the PBX along with the day’s date, an “r2d2” string, and the MD5 hash algorithm.
What is Auerswald’s Response?
Auerswald addressed the secret backdoors with an update to its firmware, dubbed version 8.2B. This firmware was issued in November of ’21. The update provides security updates for users to apply even if they do not use the specialized features. It is worth noting Auerswald’s statement did not directly reference the hidden backdoors.
