CVE-2004-0806 in cdrecord
Summary
by MITRE
cdrecord in the cdrtools package before 2.01, when installed setuid root, does not properly drop privileges before executing a program specified in the RSH environment variable, which allows local users to gain privileges.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2004-0806 resides within the cdrecord utility of the cdrtools package, a widely used set of tools for recording CDs and DVDs on Unix-like systems. This flaw affects versions prior to 2.01 and specifically manifests when cdrecord is installed with setuid root permissions, creating a critical security exposure that undermines the fundamental principle of privilege separation in Unix security models. The vulnerability represents a classic case of improper privilege handling that directly violates security best practices and can be categorized under CWE-276, which deals with inadequate privilege management.
The technical implementation of this vulnerability stems from cdrecord's failure to properly drop root privileges before executing external programs referenced through the RSH environment variable. When cdrecord runs with elevated privileges, it should immediately relinquish these permissions before performing any operations that might involve executing external commands or scripts. However, the flawed implementation allows the program to maintain root access while processing the RSH environment variable, which typically contains a command to be executed via remote shell. This design flaw creates an exploitable condition where local attackers can manipulate the RSH variable to execute arbitrary commands with root privileges, effectively bypassing the intended security boundaries that should prevent unauthorized privilege escalation.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security model of systems running affected versions of cdrtools. Attackers can leverage this weakness to execute malicious code with root privileges, potentially leading to complete system compromise, data exfiltration, or persistent backdoor installation. The vulnerability is particularly concerning because it requires no special authentication or network access to exploit, making it a low-hanging fruit for local attackers who may already have user-level access to the system. This type of attack pattern aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation of system vulnerabilities.
Mitigation strategies for CVE-2004-0806 primarily involve updating to cdrtools version 2.01 or later, where the privilege dropping mechanism has been properly implemented. System administrators should also consider removing the setuid bit from cdrecord installations when possible, as this eliminates the need for elevated privileges altogether. Additional protective measures include implementing proper access controls to limit who can execute cdrecord, monitoring for unauthorized changes to setuid binaries, and conducting regular security audits to identify other potentially vulnerable setuid programs. The vulnerability demonstrates the critical importance of proper privilege management in security-sensitive applications and serves as a reminder that even seemingly benign utilities can become attack vectors when not properly secured against privilege escalation attacks. Organizations should also consider implementing automated patch management systems to ensure timely remediation of such vulnerabilities, as the exploitation window for this type of flaw can be quite long due to its local nature and the widespread use of affected software packages.