CVE-2020-13784 in DIR-865L Ax
Summary
by MITRE
D-Link DIR-865L Ax 1.20B01 Beta devices have a predictable seed in a Pseudo-Random Number Generator.
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Analysis
by VulDB Data Team • 06/04/2020
The vulnerability identified as CVE-2020-13784 affects D-Link DIR-865L Ax 1.20B01 beta devices and represents a critical weakness in the device's cryptographic implementation. This issue stems from the use of a predictable seed within the Pseudo-Random Number Generator algorithm, which fundamentally compromises the security of the device's cryptographic operations. The problem lies in the deterministic nature of the random number generation process, where an attacker can potentially reconstruct the seed value and subsequently predict future random numbers generated by the system. This weakness directly impacts the device's ability to generate secure cryptographic keys, session identifiers, and other security-critical random values that are essential for maintaining network security and authentication integrity.
The technical flaw manifests through the predictable nature of the PRNG seed, which violates fundamental cryptographic principles outlined in industry standards such as NIST SP 800-90A and CWE-330. When a cryptographic system relies on a predictable seed, it becomes vulnerable to various attack vectors including key recovery attacks, session hijacking, and authentication bypass attempts. The specific implementation in the DIR-865L device suggests that the random number generator is initialized with a static or easily guessable value, making it susceptible to reverse engineering by threat actors who may analyze the device's behavior over time to determine the seed pattern. This vulnerability creates a pathway for attackers to compromise the device's security mechanisms and potentially gain unauthorized access to the network infrastructure.
The operational impact of this vulnerability extends beyond simple cryptographic weakness to encompass broader network security implications. An attacker who successfully exploits this predictable seed issue could potentially decrypt network traffic, forge authentication tokens, or impersonate legitimate device communications within the network. The vulnerability affects the device's ability to maintain secure communications and establish trusted connections, which are fundamental requirements for network security. This weakness is particularly concerning in enterprise environments where routers and access points serve as critical network infrastructure components, as it could enable attackers to establish persistent access points within the network or conduct man-in-the-middle attacks against legitimate communications.
Mitigation strategies for this vulnerability require immediate attention from network administrators and security teams responsible for managing D-Link DIR-865L devices. The primary recommendation involves updating the device firmware to a version that addresses the predictable seed issue and implements proper random number generation techniques. Organizations should also consider implementing network segmentation and additional monitoring controls to detect potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1566 which covers credential harvesting through social engineering and network attacks, as the predictable random number generation can facilitate various attack vectors including authentication bypass and session manipulation. Security teams should also conduct vulnerability assessments to identify other devices within their network that may be using similar cryptographic implementations and address them proactively to prevent cascading security issues across the enterprise infrastructure.