CVE-2018-11804 in Spark
Summary
by MITRE
Spark's Apache Maven-based build includes a convenience script, 'build/mvn', that downloads and runs a zinc server to speed up compilation. It has been included in release branches since 1.3.x, up to and including master. This server will accept connections from external hosts by default. A specially-crafted request to the zinc server could cause it to reveal information in files readable to the developer account running the build. Note that this issue does not affect end users of Spark, only developers building Spark from source code.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability described in CVE-2018-11804 affects Apache Spark's build infrastructure and specifically targets the convenience script 'build/mvn' used in Maven-based builds. This script incorporates a zinc server component that is designed to accelerate compilation processes by maintaining persistent compilation state. The zinc server is intended to improve developer productivity by caching compilation results and reducing build times. However, this convenience feature introduces a security risk through its default network configuration that accepts connections from external hosts without proper authentication or access controls. The vulnerability exists in release branches starting from version 1.3.x through the master branch, indicating it was present across a significant portion of Spark's development history and affected multiple versions.
The technical flaw stems from the zinc server's default configuration that allows external network connections without proper security boundaries. When developers run the build process using the 'build/mvn' script, the zinc server automatically starts and listens on network ports accessible from external hosts. This configuration creates an attack surface where malicious actors could craft specially crafted requests to interact with the zinc server. The server's design allows it to process these requests in a manner that could potentially expose file system information to unauthorized parties. Since the server operates under the privileges of the developer account running the build, any information disclosure could include sensitive files, build artifacts, or other data accessible to the developer's user context. The vulnerability represents a classic case of insecure default configurations where security considerations were not prioritized in the convenience features.
The operational impact of this vulnerability is primarily limited to developers working with Spark source code rather than end users of the Spark platform itself. However, the implications for developer environments can be significant, especially in scenarios where developers work on systems that are not properly isolated from external network access. The vulnerability could potentially expose sensitive information about the build environment, including file paths, system configurations, or potentially sensitive data that might be accessible through the zinc server's processing mechanisms. This information disclosure could aid attackers in planning more sophisticated attacks against the development environment or could reveal internal system structures that might be leveraged in broader exploitation attempts. The vulnerability also highlights the importance of considering security implications when implementing performance optimization features in development tooling.
Mitigation strategies for this vulnerability should focus on restricting network access to the zinc server and implementing proper access controls for the build environment. Developers should configure their build systems to bind the zinc server to localhost only, preventing external connections from reaching the service. The recommended approach involves modifying the build script configuration to explicitly limit the server's network interface binding or implementing firewall rules that restrict access to the zinc server ports. Organizations should also consider implementing network segmentation for development environments to isolate build systems from external network access. Additionally, regular security reviews of build infrastructure components should be conducted to identify similar insecure default configurations in other development tools. The vulnerability aligns with CWE-284, which addresses improper access control, and could be categorized under ATT&CK technique T1059 for command and scripting interpreter, as it involves exploitation of build system components through network-based attack vectors. Proper implementation of network security controls and regular security audits would effectively address this vulnerability and prevent unauthorized information disclosure in development environments.