CVE-2020-9301 in Spinnaker
Summary
by MITRE • 12/11/2020
Nolan Ray from Apple Information Security identified a security vulnerability in Spinnaker, all versions prior to version 1.23.4, 1.22.4 or 1.21.5. The vulnerability exists within the handling of SpEL expressions that allows an attacker to read and write arbitrary files within the orca container via authenticated HTTP POST requests.
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Analysis
by VulDB Data Team • 12/16/2020
The vulnerability CVE-2020-9301 represents a critical remote code execution flaw in Spinnaker's Orca component that affects versions prior to 1.23.4, 1.22.4, and 1.21.5. This security weakness stems from insufficient validation of Spring Expression Language expressions within the platform's orchestration capabilities. The vulnerability specifically targets the Orca service which handles pipeline execution and orchestration tasks in Spinnaker's continuous delivery framework. Attackers can exploit this flaw through authenticated HTTP POST requests that contain malicious SpEL expressions designed to manipulate file system operations within the container environment.
The technical implementation of this vulnerability resides in the improper sanitization of user-supplied input during SpEL expression evaluation processes. When Spinnaker processes pipeline definitions containing user-provided expressions, it fails to adequately validate or sanitize the input before executing these expressions within the runtime environment. This allows an authenticated attacker to craft malicious requests that leverage SpEL's file system access capabilities to read arbitrary files from the container's file system or write data to arbitrary locations. The vulnerability operates at the application level and leverages the inherent capabilities of Spring's expression language rather than exploiting underlying system vulnerabilities.
The operational impact of CVE-2020-9301 extends beyond simple unauthorized file access, as it provides attackers with the ability to escalate privileges and potentially compromise the entire container environment. An attacker with authenticated access can leverage this vulnerability to read sensitive configuration files, credentials, or application data stored within the Orca container. The write capabilities enable attackers to modify or inject malicious code into the container, potentially leading to full system compromise. This vulnerability particularly affects organizations using Spinnaker for continuous delivery pipelines, as it allows attackers to manipulate deployment processes and potentially gain access to production environments. The flaw aligns with CWE-20: Improper Input Validation, which specifically addresses inadequate validation of input data leading to potential security consequences.
Organizations affected by this vulnerability should prioritize immediate remediation through version updates to Spinnaker 1.23.4, 1.22.4, or 1.21.5 depending on their current deployment. Additional mitigations include implementing strict access controls and authentication mechanisms to limit who can submit pipeline definitions, monitoring for unusual file system access patterns, and conducting security audits of pipeline configurations. The vulnerability demonstrates the importance of validating user input in expression evaluation contexts and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: Windows Command Shell, as attackers can leverage the container's command execution capabilities through file system manipulation. Organizations should also consider implementing network segmentation and privilege separation to limit the potential impact if an attacker successfully exploits this vulnerability.