CVE-2000-0112 in Linux
Summary
by MITRE
The default installation of Debian GNU/Linux uses an insecure Master Boot Record (MBR) which allows a local user to boot from a floppy disk during the installation.
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Analysis
by VulDB Data Team • 04/20/2026
The vulnerability identified as CVE-2000-0112 pertains to a critical security flaw in the default installation process of Debian GNU/Linux systems. This issue stems from the insecure configuration of the Master Boot Record which serves as the initial boot code loaded by the computer's BIOS during system startup. The flaw specifically affects systems where the MBR is configured in a manner that permits local users to boot from external media such as floppy disks during the installation phase, creating an exploitable entry point for unauthorized system access.
The technical implementation of this vulnerability involves the default MBR configuration that fails to properly restrict boot options during the installation process. When a Debian system is installed with its default settings, the boot loader configuration allows for flexible boot sources including removable media such as floppy disks. This design flaw enables a local attacker with physical access to the system to insert a malicious boot floppy disk and gain control over the system boot process before the installation completes. The vulnerability resides in the boot sequence configuration rather than in the operating system kernel or application code itself.
From an operational perspective, this vulnerability presents significant security implications for systems that are physically accessible to unauthorized individuals. The local user can exploit this weakness to bypass normal authentication mechanisms and potentially install malicious software or gain root access to the system. The attack vector requires physical access to the machine, but this limitation does not mitigate the severity of the vulnerability since many systems in enterprise environments may have unsecured physical access points. This weakness is particularly concerning in scenarios where system administrators fail to properly configure the installation process or where default settings are not modified according to security best practices.
The vulnerability aligns with CWE-284, which addresses inadequate access control mechanisms in boot processes, and demonstrates how insecure default configurations can create persistent security weaknesses. From an ATT&CK framework perspective, this vulnerability maps to techniques involving bootkit creation and privilege escalation through legitimate system utilities. The attack chain typically involves physical access to the system, insertion of malicious boot media, and exploitation of the insecure MBR configuration to gain elevated privileges. Organizations should implement proper security hardening procedures during system installation, including disabling unnecessary boot sources and configuring secure boot parameters. The recommended mitigations include modifying the MBR configuration to prevent booting from removable media during installation, implementing physical security measures, and ensuring that security configurations are applied during the initial system setup rather than relying on default insecure settings. This vulnerability underscores the importance of secure configuration management and the principle of least privilege in system installation processes.