Use of a hard-coded cryptographic key pair by the telnetd_startup service allows an attacker on the local area network to obtain a root shell on the device over telnet. The builds of telnetd_startup included in the version 22.5.9.163 of the K2 firmware, and version 32.1.15.93 of the K3C firmware (possibly amongst many other releases) included both the private and public RSA keys. The remaining versions cited here redacted the private key, but left the public key unchanged. An attacker in possession of the leaked private key may, through a scripted exchange of UDP packets, instruct telnetd_startup to spawn an unauthenticated telnet shell as root, by means of which they can then obtain complete control of the device. A consequence of the limited availablility of firmware images for testing is that models and versions not listed here may share this vulnerability.
The product contains hard-coded credentials, such as a password or cryptographic key, which it uses for its own inbound authentication, outbound communication to external components, or encryption of internal data.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| K2_firmware | Phicomm | * | 22.5.9.163 (including) |
Hard-coded credentials typically create a significant hole that allows an attacker to bypass the authentication that has been configured by the product administrator. This hole might be difficult for the system administrator to detect. Even if detected, it can be difficult to fix, so the administrator may be forced into disabling the product entirely. There are two main variations:
In the Inbound variant, a default administration account is created, and a simple password is hard-coded into the product and associated with that account. This hard-coded password is the same for each installation of the product, and it usually cannot be changed or disabled by system administrators without manually modifying the program, or otherwise patching the product. If the password is ever discovered or published (a common occurrence on the Internet), then anybody with knowledge of this password can access the product. Finally, since all installations of the product will have the same password, even across different organizations, this enables massive attacks such as worms to take place. The Outbound variant applies to front-end systems that authenticate with a back-end service. The back-end service may require a fixed password which can be easily discovered. The programmer may simply hard-code those back-end credentials into the front-end product. Any user of that program may be able to extract the password. Client-side systems with hard-coded passwords pose even more of a threat, since the extraction of a password from a binary is usually very simple.