CVE-2017-12117 in JSON-RPC
Summary
by MITRE
An exploitable improper authorization vulnerability exists in miner_start API of cpp-ethereum's JSON-RPC (commit 4e1015743b95821849d001618a7ce82c7c073768). A JSON request can cause an access to the restricted functionality resulting in authorization bypass. An attacker can send JSON to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/02/2023
The CVE-2017-12117 vulnerability represents a critical authorization flaw within the cpp-ethereum client's JSON-RPC interface, specifically affecting the miner_start API endpoint. This vulnerability stems from inadequate access control mechanisms that fail to properly validate user permissions before executing privileged operations. The flaw exists in the commit hash 4e1015743b95821849d001618a7ce82c7c073768, indicating a specific code revision where the authorization checks were insufficiently implemented. The vulnerability operates at the application layer of the network stack, specifically within the Ethereum client's remote procedure call interface that allows external systems to interact with the blockchain node.
The technical implementation of this vulnerability allows an attacker to exploit a weakness in the JSON-RPC request processing pipeline where the miner_start API endpoint does not properly enforce authorization checks. When a malicious user submits a specially crafted JSON-RPC request to the miner_start endpoint, the system fails to verify whether the requesting entity possesses the necessary privileges to initiate mining operations. This improper authorization check creates a direct path for privilege escalation, enabling unauthorized users to bypass the normal access control mechanisms that should restrict mining functionality to authorized administrators. The vulnerability manifests as a failure in the principle of least privilege, where the system grants elevated permissions without proper authentication verification.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it fundamentally compromises the security posture of Ethereum nodes that rely on cpp-ethereum for their operations. An attacker who successfully exploits this vulnerability can initiate mining activities on a target node, potentially consuming significant computational resources and network bandwidth. This unauthorized mining activity could result in increased operational costs for node operators, degraded performance of the Ethereum network, and potential financial losses. The vulnerability also creates a vector for more sophisticated attacks, as unauthorized mining operations could serve as a stepping stone for additional compromise attempts. The attack surface is particularly concerning given that mining operations are typically restricted to authorized network participants and require specific administrative credentials to initiate.
Mitigation strategies for CVE-2017-12117 should focus on implementing robust access control measures within the JSON-RPC interface and ensuring proper authorization validation for all privileged operations. Network administrators should immediately apply security patches or code modifications that enforce strict authentication checks before allowing access to the miner_start API endpoint. The implementation should follow established security frameworks such as the CWE-284 (Improper Access Control) guidelines, which emphasize the importance of proper privilege management and access validation. Additionally, organizations should consider implementing network-level controls such as firewall rules that restrict access to the JSON-RPC interface to trusted administrative networks only, following the ATT&CK technique T1071.004 (Application Layer Protocol: DNS) and T1071.001 (Application Layer Protocol: Web Protocols) to limit potential exploitation vectors. Regular security auditing of API endpoints and implementation of proper logging mechanisms for monitoring unauthorized access attempts should also be enforced to detect and respond to potential exploitation attempts.