CVE-2016-10655 in clang-extra
Summary
by MITRE
The clang-extra module installs LLVM's clang-extra tools. clang-extra downloads binary resources over HTTP, which leaves it vulnerable to MITM attacks. It may be possible to cause remote code execution (RCE) by swapping out the requested resources with an attacker controlled copy if the attacker is on the network or positioned in between the user and the remote server.
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Analysis
by VulDB Data Team • 02/14/2020
The vulnerability identified as CVE-2016-10655 resides within the clang-extra module of LLVM's clang toolchain, representing a significant security flaw that undermines the integrity of software distribution processes. This module is designed to install additional clang tools that extend the functionality of the Clang compiler, but it suffers from a critical design weakness that exposes users to man-in-the-middle attack vectors. The vulnerability stems from the module's reliance on unencrypted HTTP protocols for downloading binary resources, creating an attack surface that adversaries can exploit to compromise system integrity.
The technical flaw manifests when the clang-extra module attempts to fetch external resources from remote servers using HTTP connections instead of secure HTTPS alternatives. This insecure communication channel allows attackers positioned on the same network segment or those capable of intercepting traffic to perform man-in-the-middle attacks. The vulnerability specifically enables attackers to substitute legitimate binary resources with malicious copies, leveraging the lack of cryptographic verification mechanisms during the download process. According to CWE-319, this represents a weakness in cryptographic protocols where sensitive data is transmitted in cleartext, making it susceptible to interception and modification.
The operational impact of this vulnerability extends beyond simple data interception, as it creates a pathway for remote code execution attacks that could compromise entire development environments. When an attacker successfully replaces legitimate binaries with malicious counterparts, the compromised tools could execute arbitrary code with the privileges of the user performing the installation. This risk is particularly severe in development environments where security tools are frequently updated and installed, as these systems often operate with elevated privileges. The vulnerability affects the software supply chain integrity, potentially allowing attackers to establish persistent footholds within development infrastructure and compromise the security of source code repositories and compiled applications.
Mitigation strategies for CVE-2016-10655 must address both the immediate security gap and broader supply chain protection requirements. Organizations should implement mandatory HTTPS enforcement for all external resource downloads, ensuring that the clang-extra module and similar tools utilize encrypted connections. Network administrators should deploy intrusion detection systems to monitor for suspicious HTTP traffic patterns and implement network segmentation to limit the attack surface. According to ATT&CK framework technique T1195.002, adversaries often exploit software supply chain vulnerabilities, making this particular weakness a prime target for attackers seeking to compromise development environments. Additionally, security teams should consider implementing certificate pinning mechanisms and regularly audit installed development tools to detect unauthorized modifications, as the vulnerability creates opportunities for persistent backdoors within development infrastructure.