CVE-2006-1587 in NetBSD
Summary
by MITRE
NetBSD 1.6 up to 3.0, when a user has "set record" in .mailrc with the default umask set, creates the record file with 0644 permissions, which allows local users to read the record file.
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Analysis
by VulDB Data Team • 04/21/2018
The vulnerability described in CVE-2006-1587 represents a significant privilege escalation and information disclosure issue within the NetBSD operating system across versions 1.6 through 3.0. This flaw specifically affects the mail handling functionality through the .mailrc configuration file, where users can set the "set record" option to log email interactions. The core technical issue stems from improper file permission handling during the creation of record files, which creates a security boundary violation that allows local users to access sensitive information they should not be able to read.
The technical flaw manifests when a user configures their .mailrc file with the "set record" directive while maintaining the default umask setting. Under normal circumstances, umask values typically restrict file permissions to prevent unauthorized access, but in this case, the system fails to properly apply these restrictions during record file creation. The resulting file is created with 0644 permissions, which means the owner has read and write access while group members and others have only read access. This permission set inadvertently exposes sensitive email records to all users on the system, creating a clear path for information disclosure attacks.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can facilitate more sophisticated attacks through the exposure of email communication patterns and potentially sensitive content. Local users who can read these record files may gain access to private communications, personal information, or even credentials that might be included in email exchanges. This vulnerability directly aligns with CWE-276, which addresses incorrect permission assignment, and represents a classic case of insufficient privilege separation in system services. The attack surface is particularly concerning because it leverages legitimate system functionality to create unauthorized access paths.
The security implications of CVE-2006-1587 are amplified by its location within the mail subsystem, which is often used for sensitive communications and administrative functions. When combined with other attack vectors, this vulnerability can serve as a foothold for more comprehensive system compromise. The issue demonstrates poor security hygiene in file permission handling and reflects a failure to properly implement the principle of least privilege. Organizations using affected NetBSD versions should immediately implement mitigations including restricting access to .mailrc files, modifying umask settings, or disabling the record functionality entirely. This vulnerability also connects to ATT&CK technique T1005, which covers data from local system storage, and highlights the importance of proper file access controls in preventing unauthorized information access.