CVE-2023-32698 in nfpm
Summary
by MITRE • 05/30/2023
nFPM is an alternative to fpm. The file permissions on the checked-in files were not maintained. Hence, when nfpm packaged the files (without extra config for enforcing it’s own permissions) files could go out with bad permissions (chmod 666 or 777). Anyone using nfpm for creating packages without checking/setting file permissions before packaging could result in bad permissions for files/folders.
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Analysis
by VulDB Data Team • 06/17/2023
The vulnerability identified as CVE-2023-32698 affects nFPM, a package management tool that serves as an alternative to fpm for creating software packages. This issue stems from a fundamental flaw in how the tool handles file permissions during the packaging process, creating a significant security risk for systems that rely on proper access controls. The root cause lies in nFPM's failure to preserve the original file permissions from the source files when creating packages, resulting in a complete breakdown of the permission inheritance mechanism that security-conscious administrators depend upon. This vulnerability specifically impacts systems where security through proper file permissions is critical, as the tool defaults to permissive permission settings without explicit configuration.
The technical flaw manifests when nFPM processes files for packaging without explicit permission enforcement configuration, causing it to strip away the original access control attributes and replace them with overly permissive settings such as chmod 666 or 777. This behavior directly violates security best practices and creates a dangerous situation where sensitive files may become accessible to all users on the system. The vulnerability operates at the file system level, where the tool's default behavior overrides the security context established by the original file permissions, essentially creating a privilege escalation vector through improper access control enforcement. This issue represents a classic case of inadequate input validation and permission handling that falls under the CWE-276 category for incorrect permissions.
The operational impact of this vulnerability extends beyond simple permission mismanagement to potentially compromise entire system security post-deployment. When packages created with nFPM are installed on target systems, files may end up with world-readable or world-writable permissions, creating opportunities for unauthorized access, data leakage, or malicious code execution. Attackers could exploit this weakness to modify critical system files, escalate privileges, or gain unauthorized access to sensitive data that should have been protected by more restrictive permissions. The vulnerability affects any organization using nFPM for package creation without additional security controls or manual verification of file permissions, making it particularly dangerous in enterprise environments where proper access control is mandatory.
Organizations should implement immediate mitigations including mandatory permission verification before packaging, explicit permission configuration in nFPM manifests, and regular audit procedures to validate package contents. The recommended approach involves configuring nFPM with specific permission enforcement settings, implementing automated checks that verify file permissions during the packaging process, and establishing security review procedures for all packages created with this tool. Additionally, system administrators should consider implementing monitoring solutions that detect unexpected permission changes in packaged files and establish baseline security configurations that prevent the default permissive behavior. This vulnerability highlights the critical importance of maintaining proper file system permissions as outlined in security frameworks and represents a clear violation of the principle of least privilege that should be enforced throughout the software delivery lifecycle.