CVE-2018-6331 in Buck
Summary
by MITRE
Buck parser-cache command loads/saves state using Java serialized object. If the state information is maliciously crafted, deserializing it could lead to code execution. This issue affects Buck versions prior to v2018.06.25.01.
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Analysis
by VulDB Data Team • 05/06/2025
The vulnerability identified as CVE-2018-6331 represents a critical deserialization flaw within the Buck build system's parser-cache functionality. This issue stems from the improper handling of serialized Java objects during the loading and saving of state information, creating a potential code execution vector that could be exploited by malicious actors. The affected Buck versions prior to v2018.06.25.01 demonstrate a fundamental security weakness in how the system processes serialized data, particularly when this data originates from untrusted sources. The vulnerability is categorized under CWE-502 which specifically addresses "Deserialization of Untrusted Data" and aligns with ATT&CK technique T1203 for "Exploitation for Client Execution" as it enables remote code execution through crafted serialized objects.
The technical flaw manifests when Buck's parser-cache component attempts to deserialize state information using standard Java serialization mechanisms. This process inherently trusts the serialized data without sufficient validation or sanitization, allowing attackers to craft malicious serialized objects that contain malicious payloads. When the deserialization occurs, the Java runtime executes the serialized code within the context of the Buck process, potentially enabling full system compromise. The vulnerability is particularly dangerous because it operates at the serialization layer, where the attack surface extends beyond simple input validation to encompass the entire deserialization pipeline and the underlying Java runtime environment.
The operational impact of this vulnerability extends far beyond a simple security breach, as it can lead to complete system compromise when exploited. Attackers could leverage this vulnerability to execute arbitrary code on systems running vulnerable versions of Buck, potentially gaining access to build servers, development environments, or continuous integration systems where Buck is deployed. The implications are severe for organizations relying on Buck for their build processes, as compromised build systems can serve as entry points for broader network infiltration, code injection attacks, or data exfiltration operations. This vulnerability particularly affects development environments where build tools are frequently updated and where security controls may be less stringent than in production systems.
Mitigation strategies for CVE-2018-6331 require immediate action to upgrade affected Buck installations to versions v2018.06.25.01 or later, which contain the necessary patches to address the deserialization vulnerability. Organizations should also implement additional security controls such as restricting access to build systems, implementing network segmentation, and monitoring for suspicious deserialization activities. The remediation process must include thorough testing of the updated Buck versions to ensure compatibility with existing build configurations. Security teams should also consider implementing application-level controls that restrict deserialization to trusted sources only, and establish procedures for regular security assessments of build tools and their dependencies to prevent similar vulnerabilities from emerging in the future.