CVE-2021-3684 in OpenShift Assisted Installer
Summary
by MITRE • 03/24/2023
A vulnerability was found in OpenShift Assisted Installer. During generation of the Discovery ISO, image pull secrets were leaked as plaintext in the installation logs. An authenticated user could exploit this by re-using the image pull secret to pull container images from the registry as the associated user.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability identified as CVE-2021-3684 resides within the OpenShift Assisted Installer component, specifically during the Discovery ISO generation process. This flaw represents a critical security oversight that exposes sensitive authentication credentials in plaintext format within installation logs. The OpenShift Assisted Installer serves as a crucial tool for deploying OpenShift clusters, automating the complex process of cluster initialization and configuration. The discovery of this vulnerability highlights the importance of proper credential handling during automated deployment processes where sensitive information may be inadvertently exposed through log outputs.
The technical implementation of this vulnerability stems from improper handling of image pull secrets during the ISO generation workflow. When the installer creates the Discovery ISO, it processes various configuration parameters including registry authentication credentials. These credentials, which should remain protected and encrypted during processing, are instead written to installation logs in plaintext format. This occurs because the system fails to sanitize or mask sensitive data during the logging process, creating a direct exposure of authentication tokens that can be readily extracted and utilized by unauthorized parties. The flaw essentially creates a credential leakage scenario where authentication information flows through the system without appropriate protection mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, creating a significant attack surface for malicious actors who gain access to the installation logs. An authenticated user with access to these logs can extract the image pull secrets and subsequently use them to pull container images from the associated registry. This privilege escalation allows attackers to potentially access restricted container images, perform unauthorized operations within the registry, and potentially gain further access to systems that rely on these registry credentials. The vulnerability undermines the fundamental security principle of least privilege by enabling unauthorized access to registry resources that should remain protected.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-312 (CWE-312: Cleartext Storage of Sensitive Information) and CWE-200 (CWE-200: Exposure of Sensitive Information). The flaw also aligns with ATT&CK technique T1552.001 (T1552.001: Unsecured Credentials) and T1078 (T1078: Valid Accounts) as it enables attackers to leverage legitimate credentials for unauthorized access. The vulnerability demonstrates how automated deployment tools can inadvertently create security gaps when proper input sanitization and output filtering are not implemented. Organizations using OpenShift Assisted Installer face heightened risk of credential compromise, particularly in environments where installation logs are accessible to multiple users or stored in accessible locations.
Mitigation strategies for this vulnerability should focus on implementing comprehensive credential sanitization throughout the installation process. System administrators must ensure that all sensitive information including authentication tokens, passwords, and registry credentials are properly masked or removed from log outputs. The implementation of secure logging practices including log filtering, credential obfuscation, and access controls around log files becomes critical. Additionally, organizations should implement regular security audits of automated deployment processes to identify similar credential exposure scenarios. Updates to the OpenShift Assisted Installer should include proper credential handling mechanisms that prevent plaintext exposure of authentication information during ISO generation and throughout the installation process.