Vulnerability: Hardcoded Hash in D-Link DCS-1100 and DCS-1130 Devices

Vulnerability: Hardcoded Hash in D-Link DCS-1100 and DCS-1130 Devices

CVE-2017-8415 · CRITICAL Severity

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device has a custom telnet daemon as a part of the busybox and retrieves the password from the shadow file using the function getspnam at address 0x00053894. Then performs a crypt operation on the password retrieved from the user at address 0x000538E0 and performs a strcmp at address 0x00053908 to check if the password is correct or incorrect. However, the /etc/shadow file is a part of CRAM-FS filesystem which means that the user cannot change the password and hence a hardcoded hash in /etc/shadow is used to match the credentials provided by the user. This is a salted hash of the string "admin" and hence it acts as a password to the device which cannot be changed as the whole filesystem is read only.

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