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ZeusBreakBTC

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ZeusBreakBTC: Cryptanalysis of Vulnerabilities in the NBitcoin Library for Recovering Lost Bitcoin Wallets

ZeusBreakBTC is software specifically designed to recover lost Bitcoin wallets by analyzing and exploiting vulnerabilities in the popular NBitcoin library. This paper describes identified issues in the storage and handling of private keys, deficiencies in transaction processing, cryptanalysis methods and algorithms employed by ZeusBreakBTC, and discusses the significance of this tool for security specialists and developers in the crypto ecosystem. Bitcoin is the most well-known and widely used cryptocurrency, whose security and integrity directly depend on the quality of private key storage and the correctness of software components managing transactions and addresses. One of the key libraries for working with Bitcoin on the .NET platform is NBitcoin, developed by Nicolas Dorier. Despite its popularity and widespread use, NBitcoin contains a number of vulnerabilities that can lead to loss of access to Bitcoin wallets.

ZeusBreakBTC is a software suite aimed at identifying and exploiting cryptographic and software vulnerabilities in NBitcoin to restore access to lost or inaccessible Bitcoin wallets. This work provides a detailed review of the main mechanisms used by ZeusBreakBTC, their significance, and principles of operation.

Overview of NBitcoin Vulnerabilities
NBitcoin is a convenient and functional C# library that offers APIs for creating, signing, and sending Bitcoin transactions, as well as managing keys and addresses. Among the vulnerabilities identified and exploited by ZeusBreakBTC are:

  • Unsafe storage of private keys: incorrect use of the library’s API can lead to leaks through memory, system logs, and other channels, which is critical for the secure storage of private keys.
  • External dependencies: NBitcoin’s dependencies are susceptible to man-in-the-middle attacks during code and data loading, potentially leading to tampering or modification of critical components.
  • Deserialization errors: improper handling of serialized transaction and key data may result in arbitrary code execution and security compromise.
  • Blockchain data inconsistencies between client and network: synchronization mismatches affect the accuracy of computations and transaction verification.
  • Incorrect exception handling: leads to system crashes and instability, indirectly reducing the reliability of applications built on NBitcoin.

Methodology and Principles of ZeusBreakBTC
ZeusBreakBTC implements a comprehensive approach to data analysis and recovery, utilizing cryptanalysis and software techniques:

  • Private Key Leak Analysis: The program investigates potential leaks of private keys from memory, logs, and other storage, using detection and recovery methods to regain access to lost wallets.
  • Transaction Sequence Correction: Errors in transaction nonce usage are identified and corrected, enabling recovery or re-execution of incorrect operations that may have been skipped or recorded improperly.
  • Integrity and Sum Verification of Transactions: Transactions with multiple inputs and outputs are analyzed to detect and repair corrupted or invalid data to restore locked funds.
  • Key Recovery from Reuse: Cryptographic properties are leveraged to recover private keys compromised by address and key reuse, previously considered impossible.
  • Cryptanalytic Algorithms: Specifically, the Gauss-Jacobi algorithm is applied to analyze raw or damaged data in wallet.dat files, reconstructing cryptographic parameters and restoring asset access.

Results and Practical Significance
Unlike classical recovery methods relying on seed phrases or backups, ZeusBreakBTC focuses on deep cryptanalysis of implementation errors and software component vulnerabilities. This approach increases the likelihood of successful fund recovery, particularly when traditional methods fail. Such targeted vulnerability exploitation enables:

  • A significant increase in the probability of finding and restoring lost keys and wallets.
  • Recovery of transactions and funds locked due to synchronization errors and data handling issues.
  • Identification and elimination of critical vulnerabilities, enhancing overall Bitcoin ecosystem security.

Efficiency and speed depend on factors such as the degree of data corruption, computational resources, and specialist expertise.

ZeusBreakBTC represents an important innovative tool in Bitcoin cryptanalysis and security, enabling detection and exploitation of vulnerabilities in the widely used NBitcoin library to recover lost Bitcoin wallets. Its use requires deep knowledge of cryptography, programming, and blockchain technologies. This approach emphasizes the importance of continuous monitoring, testing, and updating of software components in the crypto ecosystem to protect user assets. ZeusBreakBTC contributes significantly to incident response practices for lost cryptocurrency access, notably expanding recovery capabilities.

CVE-2019-12923 Vulnerability (bitcoin-opcodes)
This vulnerability relates to improper handling of null values in Bitcoin scripts, causing transaction processing failures. It arises when certain Bitcoin opcodes improperly process null or missing script elements, leading to crashes or incorrect behavior and potentially causing denial of service (DoS) and client instability. ZeusBreakBTC analyzes and exploits these errors and transaction processing failures to recover lost or blocked Bitcoin wallets. Specifically, problems with null value handling and Bitcoin script failures can cause incorrect or locked transactions, which ZeusBreakBTC detects and corrects. Detecting and mitigating vulnerabilities like CVE-2019-12923 is part of ZeusBreakBTC’s methodology for restoring access to lost Bitcoin assets via deep cryptanalysis of software and protocol weaknesses.
ZeusBreakBTC addresses lost Bitcoin wallet recovery via this vulnerability by:

  • Identifying transaction errors caused by null or empty opcode values that lead to transaction failures.
  • Analyzing and correcting damaged or invalid transaction data resulting from this vulnerability.
  • Applying algorithms to fix or re-execute affected transactions, restoring access to funds formerly considered lost.
    Through automated detection and deep cryptanalysis, ZeusBreakBTC raises recovery success rates for transactions corrupted by CVE-2019-12923. This enables recovering Bitcoin wallets lost due to script errors and transaction processing failures, broadening the potential for reclaiming lost digital assets.

ZeusBreakBTC detects lost Bitcoin wallets by identifying and exploiting various software and cryptographic protocol vulnerabilities. The primary types of vulnerabilities targeted include:

  • Insufficiently random private key generation: vulnerabilities due to low entropy in private key creation, making keys predictable and recoverable, especially for wallets created from roughly 2011 to 2016 when key generation flaws were common.
  • Unsafe private key storage: API misuse and memory or log mishandling leading to key leaks, facilitating external key recovery.
  • Errors in data processing and deserialization: improper handling of transaction and key data causing transaction or system failures, subject to correction by ZeusBreakBTC.
  • Blockchain data synchronization errors: inconsistencies between client and network creating invalid or locked transactions recoverable through analysis.
  • Key reuse vulnerabilities: enabling cryptanalysis recovery of private keys linked to reused addresses.
  • Use of cryptanalytic methods, including specialized algorithms like Gauss-Jacobi, to recover damaged transactions and wallet.dat files.

Randstorm Vulnerability
Randstorm is associated with the use of a vulnerable BitcoinJS JavaScript library for wallet generation in browsers circa 2011–2015. The core issue is insufficient entropy during private key generation, rendering keys predictable and vulnerable to brute-force attacks. This vulnerability affects many wallets created with BitcoinJS or dependent projects, including popular services like Blockchain.info. By exploiting Randstorm, passwords and private keys of vulnerable wallets can be recovered, granting unauthorized access. Although fixed by 2014–2016, wallets created during that period remain at risk due to weak key generation. Randstorm thus provides a methodology based on analyzing compromised random number generation and private keys to locate and recover lost or inaccessible Bitcoin wallets, enabling effective cryptanalysis of vulnerable assets.

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