CVE-2018-15796 in Cloud Foundry
Summary
by MITRE
Cloud Foundry Bits Service Release, versions prior to 2.14.0, uses an insecure hashing algorithm to sign URLs. A remote malicious user may obtain a signed URL and extract the signing key, allowing them complete read and write access to the the Bits Service storage.
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Analysis
by VulDB Data Team • 06/05/2023
The Cloud Foundry Bits Service represents a critical infrastructure component within the Cloud Foundry platform ecosystem that manages application binary transfers and storage operations. This service facilitates the uploading and downloading of application artifacts through a secure URL signing mechanism that was fundamentally compromised in versions prior to 2.14.0. The vulnerability stems from the implementation of an insecure hashing algorithm that fails to provide adequate cryptographic security for URL signing operations. This weakness creates a significant attack surface that allows malicious actors to exploit the service's authentication mechanisms and gain unauthorized access to sensitive application data stored within the Bits Service storage system.
The technical flaw manifests in the use of weak cryptographic primitives that do not meet modern security standards for digital signature generation. Specifically, the service employs a hashing algorithm that is susceptible to collision attacks and reverse engineering techniques, enabling attackers to compute valid signatures without possessing the legitimate signing key. This vulnerability directly maps to CWE-327, which addresses the use of weak or broken cryptographic algorithms, and represents a fundamental failure in the service's cryptographic implementation. The insecure hashing mechanism essentially provides attackers with a pathway to generate their own valid signatures that can be used to access any resources within the Bits Service storage, effectively bypassing the intended security controls.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with complete read and write capabilities to the entire Bits Service storage repository. This means that malicious actors can not only retrieve sensitive application binaries and configuration data but also modify or delete existing artifacts, potentially compromising multiple applications hosted within the Cloud Foundry environment. The vulnerability affects the confidentiality, integrity, and availability of the platform's application delivery mechanisms, creating a persistent threat that could remain undetected for extended periods. Attackers could leverage this access to deploy malicious code, exfiltrate proprietary application data, or disrupt service availability by corrupting stored application binaries. The scope of impact is particularly concerning given that Cloud Foundry platforms often host multiple applications and organizations, making this vulnerability a potential vector for widespread compromise.
Mitigation strategies for this vulnerability require immediate implementation of the patched version 2.14.0 or later, which addresses the cryptographic weakness through the adoption of secure hashing algorithms such as SHA-256 or higher. Organizations should conduct comprehensive assessments of their Cloud Foundry environments to identify any instances running vulnerable versions and ensure proper patch deployment across all affected systems. Security teams must implement monitoring solutions to detect anomalous access patterns that could indicate exploitation attempts, while also reviewing existing access controls and implementing principle of least privilege configurations for Bits Service operations. The remediation process should include verification that all previously generated signatures are invalidated and that new secure signing mechanisms are properly configured. Additionally, organizations should consider implementing additional security controls such as network segmentation and enhanced logging to provide defense-in-depth measures against similar vulnerabilities in other components of their Cloud Foundry infrastructure. This vulnerability demonstrates the critical importance of maintaining up-to-date cryptographic implementations and the potential consequences of relying on deprecated or insecure security mechanisms in cloud platform services.