CVE-2016-10660 in fis-parser-sass-bin
Summary
by MITRE
fis-parser-sass-bin a plugin for fis to compile sass using node-sass-binaries. fis-parser-sass-bin 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 fis-parser-sass-bin plugin represents a critical security vulnerability within the fis build system ecosystem that specifically targets the compilation process of sass files through node-sass-binaries. This plugin serves as an intermediary component that facilitates the conversion of sass syntax into css output, making it an integral part of many web development workflows. The vulnerability stems from the plugin's implementation of insecure communication protocols during the binary resource acquisition phase, where it relies on unencrypted http connections rather than secure https protocols for downloading required dependencies. This design flaw creates a fundamental weakness in the security posture of systems utilizing this plugin, as it exposes the entire compilation process to potential man-in-the-middle attacks that can occur at any point along the network path between the client system and the remote binary repository.
The technical flaw manifests in the plugin's failure to implement proper certificate validation and secure transmission mechanisms when fetching binary resources from remote servers. According to CWE-319, this vulnerability directly relates to the exposure of sensitive information through insecure communication channels, where the absence of transport layer security creates opportunities for attackers to intercept and modify network traffic. The plugin's reliance on HTTP connections without certificate verification means that any attacker positioned within the network traffic path can potentially intercept the download requests and serve maliciously modified binaries in place of the legitimate ones. This attack vector aligns with ATT&CK technique T1105 which describes the use of command and control channels to download additional tools or payloads, though in this case the malicious payload is embedded within the legitimate-looking binary download process.
The operational impact of this vulnerability extends beyond simple data interception, as it opens the door to potential remote code execution scenarios that could compromise entire development environments and production systems. When an attacker successfully substitutes legitimate binary resources with malicious copies, they can potentially execute arbitrary code on systems where the plugin operates, especially if the downloaded binaries are executed with elevated privileges or integrated into automated build processes. This risk is particularly concerning in enterprise environments where development workstations may have access to sensitive code repositories and production deployment pipelines. The vulnerability affects not only individual developers but also continuous integration systems that rely on automated plugin execution, creating widespread potential for supply chain compromise. The attack scenario described in the vulnerability description represents a classic MITM attack pattern where network position is leveraged to perform resource substitution, and according to ATT&CK framework technique T1071.004, this falls under application layer protocol manipulation where network traffic is intercepted and modified.
Mitigation strategies for this vulnerability must address both the immediate security gap and the broader architectural concerns within the plugin ecosystem. The primary recommendation involves implementing secure protocol enforcement by modifying the plugin to exclusively use HTTPS connections with certificate validation, thereby eliminating the attack surface created by unencrypted HTTP traffic. Organizations should also consider implementing network-level security controls such as certificate pinning, where specific certificate fingerprints are validated before allowing binary downloads to proceed. Additionally, implementing dependency verification mechanisms that check cryptographic hashes of downloaded binaries against known good values provides an additional layer of protection against tampered resources. The security community should also advocate for the adoption of secure supply chain practices that include source code verification and automated security scanning of third-party dependencies to prevent similar vulnerabilities from being introduced into development toolchains. This vulnerability highlights the critical importance of secure software delivery practices and demonstrates how seemingly innocuous build tool components can become significant attack vectors in the broader security landscape of modern development environments.