CVE-2015-0558 in Pirelli
Summary
by MITRE
The ADB (formerly Pirelli Broadband Solutions) P.DGA4001N router with firmware PDG_TEF_SP_4.06L.6, and possibly other routers, uses "1236790" and the MAC address to generate the WPA key.
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Analysis
by VulDB Data Team • 03/01/2022
The vulnerability identified as CVE-2015-0558 represents a critical weakness in the authentication mechanism of the ADB P.DGA4001N router firmware version PDG_TEF_SP_4.06L.6 and potentially other similar devices from the same manufacturer. This flaw stems from a predictable key generation algorithm that significantly undermines the security of wireless networks protected by WPA encryption. The router's implementation fails to utilize proper cryptographic randomness when deriving the WPA pre-shared key, creating a deterministic system that can be easily reverse-engineered by attackers. The vulnerability specifically exploits the use of a fixed string "1236790" combined with the device's MAC address to compute the wireless network password, eliminating any meaningful entropy in the key generation process.
The technical implementation of this vulnerability places the router's wireless security at risk due to a fundamental flaw in cryptographic key derivation practices. According to CWE-327, this represents a use of a broken or weak cryptographic algorithm, specifically demonstrating a weakness in key generation where predictable inputs are used to create encryption keys. The router's firmware does not implement proper key stretching or use of cryptographically secure random number generators, instead relying on a static string concatenated with the device's unique hardware identifier. This approach directly violates established security principles for wireless network protection and creates a scenario where an attacker with knowledge of the device's MAC address can easily compute the WPA password through simple mathematical operations or brute force techniques.
The operational impact of this vulnerability extends beyond simple network access, as it provides attackers with a straightforward path to unauthorized network penetration. Once an attacker discovers the router's MAC address through network reconnaissance or physical access, they can compute the WPA key without requiring additional information or complex attack vectors. This vulnerability aligns with ATT&CK technique T1046 which involves network service scanning, and T1075 which involves remote service access, as the attacker can directly access the network without needing to bypass other security controls. The consequences include unauthorized network access, potential data exfiltration, and the ability to establish persistent access points within the network infrastructure. Network administrators may remain unaware of unauthorized access for extended periods, as the attack does not generate obvious network anomalies that would trigger intrusion detection systems.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The primary recommendation involves firmware updates from the manufacturer to implement proper cryptographic key generation techniques that utilize cryptographically secure random number generators and eliminate the use of predictable constants. Network administrators should also implement additional security controls such as network segmentation, intrusion detection systems, and regular network monitoring to detect unauthorized access attempts. The vulnerability demonstrates the importance of following NIST SP 800-132 guidelines for cryptographic key management and emphasizes the need for proper entropy sources in key derivation functions. Organizations should consider implementing network access control lists, wireless intrusion prevention systems, and regular security audits to identify and remediate similar vulnerabilities in other network infrastructure devices. Additionally, the use of stronger authentication methods such as WPA2-Enterprise with proper certificate-based authentication should be considered to provide defense-in-depth against similar predictable key generation attacks.