CVE-2017-18350 in bitcoind
Summary
by MITRE
bitcoind and Bitcoin-Qt prior to 0.15.1 have a stack-based buffer overflow if an attacker-controlled SOCKS proxy server is used. This results from an integer signedness error when the proxy server responds with an acknowledgement of an unexpected target domain name.
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Analysis
by VulDB Data Team • 12/25/2022
The vulnerability identified as CVE-2017-18350 affects bitcoind and Bitcoin-Qt client software versions prior to 0151. This represents a critical security flaw that stems from improper handling of network proxy responses within the Bitcoin cryptocurrency implementation. The vulnerability specifically manifests when the software utilizes SOCKS proxy servers for network communication, creating an attack surface that can be exploited by malicious actors controlling the proxy infrastructure.
The technical root cause of this vulnerability resides in a stack-based buffer overflow condition that occurs due to an integer signedness error. When a SOCKS proxy server responds to a connection request, it includes an acknowledgement message containing information about the target domain name. The Bitcoin client software fails to properly validate the signedness of integer values used in processing this proxy response, particularly when the proxy server returns an unexpected target domain name. This improper validation allows an attacker-controlled proxy server to manipulate the integer values in such a way that they exceed the bounds of allocated memory buffers, leading to memory corruption.
The operational impact of this vulnerability is severe and potentially exploitable by remote attackers. An attacker who controls a SOCKS proxy server can craft malicious responses that trigger the buffer overflow condition when the Bitcoin client processes these responses. This memory corruption can result in arbitrary code execution on the victim machine, allowing attackers to potentially take full control of the Bitcoin client software. The vulnerability is particularly dangerous because it can be exploited without requiring any special privileges or user interaction, as the overflow occurs during normal network communication with a malicious proxy server.
From a cybersecurity perspective, this vulnerability maps directly to CWE-121 Stack-based Buffer Overflow and CWE-195 Signed to Unsigned Conversion Error, representing a classic combination of memory corruption and integer handling flaws. The attack pattern aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: PowerShell, as the exploitation could potentially involve command execution through the compromised client. The vulnerability also relates to T1071.004 Application Layer Protocol: DNS, since the domain name handling aspect connects to DNS resolution and proxy communication patterns. Organizations using Bitcoin client software must immediately update to version 0.15.1 or later to mitigate this risk, as the vulnerability can be exploited remotely and does not require any user interaction to be effective.
The remediation strategy involves updating to the patched version of Bitcoin-Qt and bitcoind software where the integer signedness error has been corrected. The fix ensures proper validation of proxy response data and appropriate handling of domain name lengths to prevent buffer overflow conditions. Additionally, network administrators should implement strict proxy server controls and monitor for unauthorized proxy usage within their Bitcoin client configurations. Security monitoring should focus on detecting unusual proxy server responses and anomalous network communication patterns that might indicate exploitation attempts.