CVE-1999-0462 in Linux
Summary
by MITRE
suidperl in Linux Perl does not check the nosuid mount option on file systems, allowing local users to gain root access by placing a setuid script in a mountable file system, e.g. a CD-ROM or floppy disk.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-0462 represents a critical security flaw in the Linux Perl implementation that affects the suidperl utility. This issue stems from the improper handling of the nosuid mount option during file system operations, creating a privilege escalation vector that can be exploited by local attackers. The vulnerability specifically targets the interaction between the suidperl mechanism and mount options, allowing unauthorized users to execute setuid scripts with elevated privileges.
The technical root cause of this vulnerability lies in the suidperl utility's failure to validate mount options when executing setuid scripts. When a file system is mounted with the nosuid option, it explicitly prevents the execution of setuid binaries for security reasons. However, the suidperl implementation in Linux Perl bypasses this protection mechanism, enabling local users to place malicious setuid scripts on file systems that should normally restrict such operations. This flaw operates at the kernel level where mount options should enforce security policies but instead allow bypass through the Perl execution environment.
From an operational perspective, this vulnerability creates a significant threat landscape for Linux systems running affected Perl implementations. Local attackers can exploit this weakness by creating malicious setuid scripts on removable media such as CD-ROMs or floppy disks, then executing these scripts to gain root access to the system. The attack vector is particularly concerning because it leverages legitimate system components while circumventing standard security controls. This vulnerability essentially undermines the fundamental principle of mount option enforcement, where nosuid should prevent privilege escalation through setuid binaries.
The impact of this vulnerability aligns with CWE-276, which addresses improper privilege management, and can be mapped to ATT&CK technique T1068, which covers privilege escalation through local exploitation. This flaw represents a classic case of insufficient input validation and improper privilege handling in system utilities. The vulnerability demonstrates how the interaction between different system components can create unexpected security gaps, particularly when mount options are not properly enforced across all execution paths.
Mitigation strategies for this vulnerability should focus on immediate system hardening measures including updating Perl implementations to versions that properly respect mount options, implementing strict monitoring of setuid script execution, and ensuring that removable media cannot be mounted with setuid permissions. System administrators should also consider implementing additional controls such as disabling suidperl entirely or using alternative execution mechanisms that properly enforce security policies. The fix typically involves modifying the suidperl utility to check mount options before executing setuid scripts, ensuring that the nosuid mount option is respected regardless of the execution context. This vulnerability underscores the importance of comprehensive security testing across all system components and the critical need for proper privilege management in system utilities.