CVE-2020-16271 in KeePassRPC
Summary
by MITRE
The SRP-6a implementation in Kee Vault KeePassRPC before 1.12.0 generates insufficiently random numbers, which allows remote attackers to read and modify data in the KeePass database via a WebSocket connection.
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Analysis
by VulDB Data Team • 08/04/2020
The vulnerability identified as CVE-2020-16271 resides within the Secure Remote Password protocol version 6a implementation found in Kee Vault KeePassRPC prior to version 1.12.0. This flaw represents a critical weakness in the cryptographic random number generation process that underpins secure authentication mechanisms. The vulnerability specifically targets the pseudo-random number generator used during the SRP authentication handshake, creating exploitable conditions that compromise the integrity and confidentiality of authenticated communications. The implementation fails to utilize cryptographically secure random number generation methods, instead relying on insufficiently random values that can be predicted or reconstructed by malicious actors.
The technical flaw manifests through the inadequate entropy sources used in the SRP-6a protocol execution, particularly during the generation of the random values required for the authentication process. This weakness allows attackers to potentially reconstruct the session keys used for secure communication, enabling them to intercept, modify, or inject data within the WebSocket connection between the client and the KeePass database server. The vulnerability operates at the cryptographic protocol level where the security of the entire authentication mechanism is compromised due to the predictable nature of the generated random numbers. The insufficient randomness creates a condition where an attacker can potentially determine the session keys used for encryption and authentication, thereby gaining unauthorized access to the protected database contents.
The operational impact of this vulnerability extends beyond simple data exposure to encompass full read and write capabilities within the KeePass database through the compromised WebSocket interface. Attackers can leverage this weakness to not only access sensitive password information but also to modify or delete entries within the database, potentially leading to complete compromise of the password management system. The vulnerability is particularly dangerous because it operates at the point of authentication, where attackers can establish persistent access to the password database without requiring additional credentials or privileges. This weakness undermines the fundamental security assumptions of the SRP protocol, which is designed to provide secure authentication without transmitting passwords over the network, making the compromise of the random number generation process particularly devastating.
Mitigation strategies for CVE-2020-16271 require immediate patching of the KeePassRPC component to version 1.12.0 or later, which addresses the insufficient random number generation issue through the implementation of proper cryptographically secure random number generators. Organizations should also implement network monitoring to detect unauthorized WebSocket connections and authentication attempts that might indicate exploitation attempts. The vulnerability aligns with CWE-330, which addresses insufficient entropy in random number generators, and represents a clear violation of the principle that cryptographic operations require high-quality random numbers to maintain security guarantees. From an ATT&CK framework perspective, this vulnerability maps to technique T1075 for legitimate credentials and T1566 for credential access through network boundaries, highlighting the need for both cryptographic hardening and network security controls. Additionally, system administrators should conduct thorough security assessments of all authentication mechanisms and ensure that cryptographic libraries and implementations meet industry standards for random number generation, particularly in environments where sensitive credential data is stored and managed through network protocols.