CVE-2004-0228 in Linux
Summary
by MITRE
Integer signedness error in the cpufreq proc handler (cpufreq_procctl) in Linux kernel 2.6 allows local users to gain privileges.
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Analysis
by VulDB Data Team • 04/08/2025
The vulnerability identified as CVE-2004-0228 represents a critical integer signedness error within the Linux kernel's cpufreq subsystem, specifically affecting the cpufreq_procctl function in kernel versions 2.6. This flaw exists in the handling of processor frequency scaling parameters through the /proc filesystem interface, creating a potential privilege escalation vector for local attackers. The issue stems from improper validation of integer values when processing cpufreq control operations, allowing malicious code to manipulate signed integer variables in ways that bypass intended security checks.
The technical root cause of this vulnerability lies in the cpufreq proc handler's failure to properly validate input parameters when processing frequency scaling requests through the /proc interface. When local users submit crafted frequency values, the kernel's integer handling routines interpret these values incorrectly due to the signedness error, potentially allowing the execution of code with elevated privileges. This type of vulnerability falls under CWE-191, which specifically addresses integer underflow conditions, and more broadly relates to CWE-190, which covers integer overflow and underflow issues. The flaw demonstrates a classic case of improper input validation where signed integer variables are not adequately checked before being used in critical operations that determine system access rights.
The operational impact of CVE-2004-0228 is significant for any Linux system running kernel 2.6 or earlier versions, as it provides local attackers with a direct path to privilege escalation. An attacker with normal user privileges could exploit this vulnerability to execute arbitrary code with root-level permissions, effectively compromising the entire system. This vulnerability is particularly dangerous in multi-user environments where users might have shell access but not administrative rights, as it creates a backdoor for gaining full system control. The exploitability of this flaw is enhanced by the fact that it requires no special privileges beyond normal user access to the system, making it a particularly attractive target for malicious actors.
Mitigation strategies for this vulnerability involve immediate kernel upgrades to versions that contain the patched cpufreq implementation, specifically kernel versions 2.6.6 and later. System administrators should prioritize applying security patches as soon as they become available, as the vulnerability exists in the core kernel functionality and cannot be effectively mitigated through configuration changes alone. The patch addresses the integer signedness error by implementing proper input validation and ensuring that frequency scaling parameters are correctly interpreted regardless of their signedness. Organizations should also implement monitoring for suspicious process behavior and system access patterns that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to technique T1068, which covers 'Exploitation for Privilege Escalation', and T1547.001, related to 'Registry Run Keys / Startup Folder' if attackers establish persistence. System hardening measures including restricting access to the cpufreq interface and implementing proper privilege separation should also be considered as additional defensive measures.