CVE-2009-3200 in Ts-239 Pro Turbo Nas
Summary
by MITRE
The QNAP TS-239 Pro and TS-639 Pro with firmware 2.1.7 0613, 3.1.0 0627, and 3.1.1 0815 create an undocumented recovery key and store it in the ENCK variable in flash memory, which allows local users to bypass the passphrase requirement and decrypt the hard drive by reading this variable, deobfuscating the key, and running a cryptsetup luksOpen command.
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Analysis
by VulDB Data Team • 06/12/2017
The vulnerability described in CVE-2009-3200 represents a critical security flaw in QNAP Network Attached Storage (NAS) devices, specifically the TS-239 Pro and TS-639 Pro models. This issue stems from improper implementation of disk encryption mechanisms within the firmware of these devices, creating a fundamental weakness that undermines the security assurances typically expected from full disk encryption solutions. The vulnerability affects firmware versions 2.1.7 0613, 3.1.0 0627, and 3.1.1 0815, indicating that this was a persistent flaw across multiple iterations of the device's software infrastructure.
The technical implementation of this vulnerability involves the creation of an undocumented recovery key that is stored in a specific variable named ENCK within the device's flash memory. This design flaw violates fundamental security principles by storing encryption keys in a manner that is not only accessible to authorized administrators but also to local users with physical access to the device. The ENCK variable essentially serves as a backdoor mechanism that bypasses the normal passphrase verification process required for accessing encrypted data. The recovery key is not properly secured or obfuscated within the storage medium, making it directly readable by anyone with sufficient technical knowledge and local access to the device's memory structures.
From an operational perspective, this vulnerability creates a severe risk for organizations relying on QNAP NAS devices for data storage and protection. Local users who gain access to the device can exploit this flaw to decrypt hard drives without proper authorization, effectively nullifying the encryption protection that users expect from their storage systems. The attack vector is particularly concerning because it requires only local access to the device rather than network-based exploitation, making it accessible to insiders or individuals with physical access. The process of exploitation involves reading the ENCK variable from flash memory, deobfuscating the stored key, and executing a cryptsetup luksOpen command, which demonstrates the straightforward nature of the attack and its potential for widespread abuse.
The vulnerability aligns with CWE-310, which addresses cryptographic weaknesses, and specifically relates to improper key management within storage systems. From an adversarial perspective, this flaw maps directly to ATT&CK technique T1003.002 for Credential Access - OS Credential Dumping, as it allows unauthorized access to cryptographic keys stored on the system. The implications extend beyond simple data theft to encompass complete system compromise, as the attacker can access all encrypted data without requiring knowledge of user passphrases. Organizations implementing these devices may be unaware of the vulnerability, as the recovery key mechanism was undocumented, creating a false sense of security among administrators who might believe their encryption is properly configured and protected.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from QNAP to address the insecure key storage implementation. System administrators should implement strict physical access controls to prevent unauthorized individuals from gaining access to the devices. Additional measures include monitoring for unauthorized access attempts and implementing network-level controls to limit local access to the storage devices. Organizations should also consider the broader implications of using encrypted storage solutions and ensure that their security policies account for potential weaknesses in device firmware. The vulnerability demonstrates the critical importance of proper key management practices and the necessity of thorough security testing for embedded systems before deployment in production environments where sensitive data is stored.