CVE-2019-16753 in Decentralized Anonymous Payment System
Summary
by MITRE
An issue was discovered in Decentralized Anonymous Payment System (DAPS) through 2019-08-26. The content to be signed is composed of a representation of strings, rather than being composed of their binary representations. This is a weak signature scheme design that would allow the reuse of signatures in some cases (or even the reuse of signatures, intended for one type of message, for another type). This also affects Private Instant Verified Transactions (PIVX) through 3.4.0.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability identified as CVE-2019-16753 represents a critical cryptographic weakness in the Decentralized Anonymous Payment System (DAPS) and its implementation in Private Instant Verified Transactions (PIVX) up to version 3.4.0. This flaw stems from a fundamental design error in how digital signatures are generated and validated within these cryptocurrency systems. The core issue lies in the improper handling of message representation during the signing process, where the system utilizes string representations rather than binary representations of data when computing cryptographic signatures. This design choice creates a significant security vulnerability that directly violates established cryptographic best practices and industry standards.
The technical flaw manifests when signatures are computed using string representations instead of their corresponding binary encodings, creating opportunities for signature forgery and cross-message signature reuse. This weakness allows malicious actors to potentially take a valid signature created for one type of message and successfully apply it to another message type, effectively bypassing the cryptographic integrity mechanisms that should protect against such attacks. The vulnerability operates at the cryptographic protocol level, specifically impacting the signature verification process and undermining the fundamental security assumptions of the digital signature scheme. This issue falls under CWE-327, which addresses the use of weak cryptographic algorithms and improper implementation of cryptographic functions, and aligns with ATT&CK technique T1552.004 related to credentials from password storage providers.
The operational impact of this vulnerability extends beyond simple signature validation failures, potentially allowing attackers to manipulate transaction records and compromise the integrity of the entire payment system. In the context of PIVX and DAPS implementations, this weakness could enable unauthorized parties to create fraudulent transactions that would appear legitimate to the network, leading to potential financial losses and system compromise. The vulnerability affects the core trust model of these cryptocurrencies, as it undermines the ability to verify message authenticity and integrity. Attackers could exploit this weakness to perform replay attacks, modify transaction parameters, or create invalid signatures that would be accepted by the network due to the flawed signature verification process. This type of vulnerability particularly threatens systems that rely on digital signatures for transaction authentication and prevents the system from properly distinguishing between different message types during the verification phase.
Mitigation strategies for this vulnerability require immediate implementation of proper cryptographic practices including the use of binary representations during signature computation and verification processes. System administrators should upgrade to patched versions of PIVX and DAPS implementations that correctly handle message representations using proper binary encoding before computing cryptographic signatures. The fix should ensure that all signature generation and verification operations use consistent binary representations of messages to prevent cross-message signature reuse attacks. Additionally, implementing proper input validation and message type checking mechanisms can help prevent exploitation of this weakness. Organizations should also conduct thorough security audits of their cryptographic implementations to identify similar design flaws and ensure compliance with established cryptographic standards such as those defined in NIST SP 800-57 and ISO/IEC 14888-3. The vulnerability demonstrates the critical importance of proper cryptographic implementation and the severe consequences that can arise from seemingly minor design decisions in security-critical systems.