CVE-2014-6251 in CPUMiner
Summary
by MITRE
Stack-based buffer overflow in CPUMiner before 2.4.1 allows remote attackers to have an unspecified impact by sending a mining.subscribe response with a large nonce2 length, then triggering the overflow with a mining.notify request.
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Analysis
by VulDB Data Team • 03/14/2019
The vulnerability identified as CVE-2014-6251 represents a critical stack-based buffer overflow flaw in CPUMiner software versions prior to 2.4.1. This vulnerability specifically targets the mining.subscribe response handling mechanism within the mining protocol implementation, where an attacker can manipulate the nonce2 field to exceed allocated buffer boundaries. The flaw resides in the client-side processing logic that fails to properly validate or constrain the length of the nonce2 parameter received during the subscription phase of the mining protocol. The buffer overflow occurs when the mining.notify request is subsequently processed, triggering the exploitation of the previously established overflow condition. This vulnerability demonstrates a classic stack corruption issue that can potentially lead to arbitrary code execution or service disruption, making it particularly dangerous in mining pool environments where multiple clients interact with mining servers.
The technical implementation of this vulnerability follows a specific attack pattern that leverages the mining protocol's message handling sequence. During the initial mining.subscribe response, the client receives a response containing a nonce2 field that is not properly bounded in terms of length. When an attacker crafts a malicious response with an oversized nonce2 value, the software's buffer allocation mechanism fails to account for this excessive input. The subsequent mining.notify request serves as the trigger mechanism that forces the system to process the corrupted buffer contents, causing the stack overflow condition to manifest. This pattern aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory. The vulnerability exploits the fundamental principle that the mining protocol implementation does not enforce proper input validation on critical parameters that are processed during subsequent operations.
The operational impact of CVE-2014-6251 extends beyond simple denial of service scenarios, potentially enabling remote code execution within the mining client environment. Attackers can leverage this vulnerability to inject malicious code into the mining process, potentially compromising the entire mining operation or redirecting computational resources to unauthorized purposes. In mining pool contexts, this vulnerability could allow attackers to corrupt multiple client instances simultaneously, leading to significant operational disruption and potential financial losses. The vulnerability's remote exploitability means that attackers do not require local system access, making it particularly dangerous in distributed mining environments. The unspecified impact mentioned in the CVE description reflects the potential for various outcomes including system crashes, data corruption, or complete compromise of the mining client software. This aligns with ATT&CK technique T1059, which covers the execution of malicious code through compromised client software, and demonstrates how mining protocol vulnerabilities can be leveraged for broader operational attacks.
Mitigation strategies for CVE-2014-6251 focus primarily on updating to CPUMiner version 2.4.1 or later, which includes proper bounds checking for the nonce2 parameter. System administrators should implement network-level monitoring to detect unusual mining protocol traffic patterns that might indicate exploitation attempts. The implementation of input validation measures within the mining protocol handling code is essential, particularly around parameter length constraints for nonce2 fields. Additional defensive measures include network segmentation to limit exposure of mining clients to untrusted networks and regular security audits of mining software configurations. Organizations should also consider implementing intrusion detection systems that can identify anomalous mining protocol behavior patterns. The vulnerability underscores the importance of proper software testing and validation in cryptocurrency mining applications, particularly in environments where multiple clients interact with centralized mining servers. Security patches should be applied immediately upon release, as the vulnerability's remote exploitability makes it a high-priority target for attackers in the cryptocurrency mining ecosystem.