CVE-2017-12112 in JSON-RPC
Summary
by MITRE
An exploitable improper authorization vulnerability exists in admin_addPeer 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-2017-12112 vulnerability represents a critical improper authorization flaw within the cpp-ethereum client's JSON-RPC administrative interface, specifically affecting the admin_addPeer 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 codebase revision where the authorization checks were insufficiently implemented. The vulnerability manifests when an attacker sends a specially crafted JSON-RPC request to the admin_addPeer endpoint, which should typically require administrative privileges to execute but instead accepts requests from unauthorized users.
The technical implementation of this vulnerability involves a failure in the authentication and authorization framework within the JSON-RPC handler for the admin_addPeer function. This API endpoint is designed to allow administrators to add new peer nodes to the Ethereum network, a functionality that should be restricted to authorized users with appropriate privileges. However, the vulnerability allows any remote attacker to bypass these authorization checks and execute the peer addition functionality without proper authentication. The flaw operates at the application layer where the JSON-RPC interface processes incoming requests, making it particularly dangerous as it can be exploited through standard network communication channels without requiring physical access or advanced technical skills.
The operational impact of CVE-2017-12112 extends beyond simple unauthorized access to potentially compromise the entire Ethereum node's network integrity. An attacker exploiting this vulnerability can add malicious peer nodes to the network, potentially leading to man-in-the-middle attacks, data manipulation, or network disruption. The vulnerability aligns with CWE-285, which specifically addresses improper authorization issues in software systems, and can be mapped to ATT&CK technique T1078 for valid accounts and T1566 for social engineering approaches that could be used to exploit the vulnerability. The consequences include potential network partitioning, unauthorized node addition, and the possibility of attackers establishing persistent access points within the Ethereum network infrastructure.
Mitigation strategies for this vulnerability require immediate implementation of proper authentication controls and access validation within the JSON-RPC interface. Network administrators should ensure that all administrative API endpoints require proper authentication tokens or certificates before execution, with the system validating user credentials against a secure authentication backend. The fix involves implementing robust authorization checks that verify user privileges before allowing access to sensitive functions like admin_addPeer, ensuring that only authenticated administrators can execute these operations. Additionally, organizations should implement network segmentation to limit access to administrative interfaces, deploy intrusion detection systems to monitor for suspicious JSON-RPC requests, and regularly audit access logs to identify potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and authorization checking in distributed network protocols, particularly those handling peer-to-peer network management functions.