CVE-2019-15802 : Vulnerability Insights and Analysis
Learn about CVE-2019-15802 affecting Zyxel GS1900 devices. Discover how a cryptographic key vulnerability allows for password decryption in firmware versions prior to 2.50(AAHH.0)C0.
A vulnerability has been identified in Zyxel GS1900 devices prior to firmware version 2.50(AAHH.0)C0, allowing for the decryption of encrypted passwords.
Understanding CVE-2019-15802
This CVE involves a cryptographic key vulnerability in Zyxel GS1900 devices that can lead to password decryption.
What is CVE-2019-15802?
The vulnerability in Zyxel GS1900 devices allows attackers to decrypt previously encrypted passwords due to a hardcoded cryptographic key used in the firmware.
The Impact of CVE-2019-15802
The exploitation of this vulnerability could result in unauthorized access to sensitive information, including decrypted passwords stored in configuration backups or the firmware itself.
Technical Details of CVE-2019-15802
This section provides detailed technical information about the vulnerability.
Vulnerability Description
The vulnerability lies in the utilization of a pre-set cryptographic key within the sal_util_str_encrypt() function in the libsal.so.0.0 library to hash and encrypt passwords.
Affected Systems and Versions
- Affected System: Zyxel GS1900 devices
- Affected Versions: Firmware versions prior to 2.50(AAHH.0)C0
Exploitation Mechanism
The encryption process involves the use of parameters such as salt, IV, and key data for AES256 encryption in CBC mode. Attackers can decrypt all previously encrypted passwords by accessing these parameters.
Mitigation and Prevention
Protecting against and addressing the CVE-2019-15802 vulnerability is crucial for maintaining security.
Immediate Steps to Take
- Update Zyxel GS1900 devices to firmware version 2.50(AAHH.0)C0 or later to mitigate the vulnerability.
- Change all passwords that may have been encrypted using the vulnerable firmware.
Long-Term Security Practices
- Implement strong password policies and regular password changes.
- Monitor for any unauthorized access or unusual activity on the network.
Patching and Updates
- Regularly check for firmware updates and security patches from Zyxel to address known vulnerabilities.