CVE-2004-2731 in Linux
Summary
by MITRE
Multiple integer overflows in Sbus PROM driver (drivers/sbus/char/openprom.c) for the Linux kernel 2.4.x up to 2.4.27, 2.6.x up to 2.6.7, and possibly later versions, allow local users to execute arbitrary code by specifying (1) a small buffer size to the copyin_string function or (2) a negative buffer size to the copyin function.
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Analysis
by VulDB Data Team • 06/13/2024
The vulnerability identified as CVE-2004-2731 represents a critical security flaw within the Linux kernel's Sbus PROM driver component, specifically in the openprom.c file that handles OpenProm interface operations. This issue affects kernel versions from 2.4.x through 2.6.7, creating a persistent risk across multiple kernel generations where local attackers can exploit integer overflow conditions to gain elevated privileges. The vulnerability stems from improper input validation within kernel space functions that process buffer operations for system bus communication protocols, particularly affecting systems utilizing sun4m architecture with Sbus hardware components.
The technical exploitation occurs through two distinct pathways that leverage integer overflow conditions in kernel memory management functions. The first vector involves specifying an intentionally small buffer size to the copyin_string function, while the second exploits negative buffer size parameters passed to the copyin function. Both scenarios create situations where integer arithmetic operations exceed the maximum representable value for signed integers, resulting in unexpected behavior that can be manipulated to overwrite critical memory locations. These integer overflows occur in kernel space where privilege escalation is automatic, allowing local users to execute arbitrary code with kernel-level privileges. The vulnerability directly maps to CWE-190, which categorizes integer overflow conditions, and represents a classic example of how improper integer handling in kernel drivers can lead to privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to bypass kernel security mechanisms and potentially compromise entire system operations. Local users who can access the system gain the ability to execute malicious code with root privileges, effectively neutralizing any local security restrictions. The exploitation requires minimal privileges since it targets a local kernel component, making it particularly dangerous in multi-user environments where users might not have direct access to kernel interfaces. Systems utilizing Sbus hardware, primarily older sun4m systems, become particularly vulnerable, though the broad kernel version range suggests this flaw affected numerous installations. The vulnerability's persistence across kernel versions 2.4.x through 2.6.7 indicates that it was not properly addressed in the kernel security updates, creating a window of exposure that could be exploited by attackers with local access.
Mitigation strategies for CVE-2004-2731 require immediate kernel updates to versions that contain patches addressing the integer overflow conditions in the Sbus PROM driver. System administrators should prioritize upgrading to kernel versions beyond 2.6.8 where the specific vulnerabilities in openprom.c have been corrected through proper input validation and integer boundary checking. Additionally, implementing runtime protections such as kernel address space layout randomization and stack canaries can provide defense-in-depth measures against exploitation attempts. Network segmentation and access control policies should limit local user access to systems where kernel-level vulnerabilities exist, particularly on legacy hardware utilizing Sbus interfaces. The vulnerability's classification under ATT&CK technique T1068, which covers local privilege escalation, emphasizes the need for comprehensive system hardening measures including regular security audits, monitoring for suspicious kernel-level activity, and maintaining updated security patches across all system components. Organizations should also consider implementing kernel module signing and trusted boot processes to prevent unauthorized kernel modifications that could exploit similar vulnerabilities in the future.