From this webpage screenshot, the following key information about the vulnerability can be obtained: 1. Vulnerability Title: Hard-Coded Credential Vulnerability in E-Lins Routers 2. Affected Versions: - H685 Router < v3.2.337 - H685f Router < v3.2.248 - H820 Router < v3.3.69 - H820Q Router < v3.2.272 - H820Q0 Router < v3.2.259 - H900 Router < 3.2.241 - H700 Router < 3.2.243 - H720 Router < 3.2.239 - H750 Router < 3.2.241 3. Vulnerability Description: - Multiple router models from E-Lins Technology Co., Ltd., including H685, H685f, H820, H820Q, H820Q0, H900, H700, H720, and H750, are affected by a hard-coded vulnerability. - A hidden backend can be accessed via a specific URL using credentials (oemadmin:crpwd) derived from a password hash stored in the shadow file. - The hidden account allows unauthorized users to modify critical router settings, such as MAC addresses and logo images, and gain access to features intended for regular users. - If default configurations remain unchanged, additional hard-coded accounts such as guest:guest may still permit access to the router’s normal administrative interface. 4. Exploitation Method: - The hidden OEM backend account is accessible via the path . - The username and password for this account are stored in the shadow file. - The password hash for was extracted and cracked using John the Ripper, revealing the password . - With the password , one can log into the hidden backend at the URL: . - Access to the hidden backend enables modification of MAC addresses, logo images, and features available to regular users. - The account can also log into the standard web interface. - Additionally, if the default configuration has not been changed, other accounts from the shadow file, such as , may still be active and allow access to the normal backend. 5. Exploitation Examples: - Successful login to the hidden OEM backend using credentials . - Normal web system login using the same credentials. - Login using credentials if default settings were not altered. This information provides a detailed description of the nature of the hard-coded credential vulnerability in E-Lins routers, the affected versions, exploitation methods, and potential attack scenarios.