CVE-2015-6964 in MultiBit
Summary
by MITRE • 09/25/2023
MultiBit HD before 0.1.2 allows attackers to conduct bit-flipping attacks that insert unspendable Bitcoin addresses into the list that MultiBit uses to send fees to the developers. (Attackers cannot realistically steal these fees for themselves.) This occurs because there is no message authentication code (MAC).
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Analysis
by VulDB Data Team • 09/25/2024
The vulnerability identified as CVE-2015-6964 affects MultiBit HD versions prior to 0.1.2 and represents a significant security flaw in the cryptocurrency wallet's handling of transaction fee management. This issue stems from the absence of proper message authentication code implementation within the software's communication protocols, creating an exploitable weakness that allows malicious actors to manipulate the fee distribution system. The vulnerability specifically targets the mechanism by which MultiBit HD manages the list of addresses used to send developer fees, enabling attackers to inject unspendable Bitcoin addresses into this critical list through bit-flipping techniques.
The technical implementation of this vulnerability demonstrates a fundamental failure in cryptographic security practices within the MultiBit HD wallet software. Bit-flipping attacks exploit the lack of message authentication codes to modify data during transmission or storage, allowing attackers to alter the fee address list without detection. This flaw operates at the protocol level where the wallet should verify the integrity of fee distribution addresses before accepting them. The absence of MAC validation means that any modification to the fee address list can occur silently, with the software accepting maliciously altered data as legitimate. This represents a classic weakness in cryptographic design where authentication mechanisms are missing from critical data flows, making the system vulnerable to man-in-the-middle attacks and data manipulation.
The operational impact of CVE-2015-6964 extends beyond simple data corruption, as it fundamentally undermines the trust model that cryptocurrency wallets rely upon for secure transaction processing. While attackers cannot directly steal the fees intended for developers, the insertion of unspendable addresses creates a persistent disruption to the wallet's normal operation and fee collection mechanisms. This vulnerability affects the wallet's ability to properly route developer fees, potentially causing transaction failures or redirecting fees to addresses that cannot be accessed by anyone, including the legitimate developers. The attack vector demonstrates how insufficient cryptographic controls can create long-term security implications for cryptocurrency systems, as compromised fee distribution mechanisms can affect wallet functionality and developer revenue streams. The vulnerability also highlights the importance of proper input validation and data integrity checks in financial applications, where even seemingly minor flaws can have significant operational consequences.
Security mitigations for this vulnerability require implementing proper message authentication code mechanisms throughout the MultiBit HD software's communication channels and data storage processes. The solution involves adding cryptographic signatures to all fee address lists and implementing verification procedures that validate the integrity of data before acceptance. This approach aligns with established security practices outlined in the CWE (Common Weakness Enumeration) catalog under weakness category CWE-311, which addresses the absence of cryptographic protection of sensitive data. Organizations should also implement continuous monitoring and integrity checking mechanisms to detect unauthorized modifications to critical wallet data structures. The fix should include robust validation of all external data inputs and implementation of secure communication protocols that prevent bit-flipping attacks from succeeding. Additionally, this vulnerability demonstrates the importance of following ATT&CK framework principles for defensive security measures, particularly in the area of credential access and defense evasion techniques that attackers might use to manipulate wallet functionality. The remediation process must ensure that all data flows containing fee distribution information include proper authentication and integrity verification mechanisms to prevent similar attacks in the future.