CVE-2019-7306 in Byobu
Summary
by MITRE
Byobu Apport hook may disclose sensitive information since it automatically uploads the local user's .screenrc which may contain private hostnames, usernames and passwords. This issue affects: byobu
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Analysis
by VulDB Data Team • 05/31/2024
The vulnerability identified as CVE-2019-7306 represents a critical information disclosure flaw within the Byobu application's Apport hook functionality. This issue stems from the automatic upload of local user configuration files without proper sanitization or access controls, creating a significant security risk for systems utilizing this tool. The vulnerability specifically targets the .screenrc file which serves as a configuration file for the GNU Screen terminal multiplexer, commonly used in conjunction with Byobu for enhanced terminal session management.
The technical flaw manifests in the improper handling of sensitive data within the Apport hook mechanism, which is designed to automatically collect and report system information for debugging purposes. When Byobu's Apport hook executes, it indiscriminately uploads the user's .screenrc file to remote servers, potentially exposing confidential information including private hostnames, usernames, and passwords. This behavior violates fundamental security principles of least privilege and data protection, as it automatically exposes user-specific configuration data without explicit user consent or awareness.
The operational impact of this vulnerability extends beyond simple information disclosure, as the exposed credentials and hostnames could enable attackers to conduct further reconnaissance and potentially gain unauthorized access to systems. The presence of passwords and usernames in configuration files creates opportunities for credential reuse attacks, while private hostnames may reveal internal network topology information that could be leveraged for targeted attacks. This vulnerability particularly affects environments where Byobu is deployed in multi-user scenarios or where users maintain sensitive configuration data in their terminal session management tools.
Security professionals should consider this vulnerability in the context of CWE-200, which addresses information exposure, and align it with ATT&CK techniques related to credential access and reconnaissance. The flaw demonstrates poor input validation and output sanitization practices that violate security best practices for configuration management and automated data collection processes. Organizations should implement immediate mitigations including disabling the problematic Apport hook functionality, manually reviewing and sanitizing .screenrc files, and implementing proper access controls for configuration files. Additionally, regular security audits should verify that automated data collection mechanisms do not inadvertently expose sensitive information, and user education programs should emphasize the importance of reviewing configuration file contents before enabling automated reporting features.