Weak Password Encryption in Zyxel GS1900 Devices

CVE-2019-15802

Summary

A vulnerability exists in Zyxel GS1900 devices where the firmware uses a hardcoded cryptographic key for password hashing and encryption. This flaw affects the sal_util_str_encrypt() function in libsal.so.0.0, as the device employs AES256 encryption in CBC mode with known parameters including the salt, IV, and key data. Consequently, all encrypted passwords, including those embedded in configuration backups, can be decrypted, posing significant security risks.

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