CVE-2005-4776 in NetBSD
Summary
by MITRE
Integer overflow in the FreeBSD compatibility code (freebsd_misc.c) in NetBSD-current, NetBSD-3, NetBSD-2.0, and NetBSD-2 before 20050913; and NetBSD-1.6 before 20050914; allows local users to cause a denial of service (heap corruption or system crash) and possibly gain root privileges.
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Analysis
by VulDB Data Team • 07/16/2018
The vulnerability described in CVE-2005-4776 represents a critical integer overflow flaw within the FreeBSD compatibility layer of NetBSD operating systems. This issue resides in the freebsd_misc.c source file which implements compatibility functions to support FreeBSD system calls and behaviors within the NetBSD kernel. The vulnerability affects multiple NetBSD versions including current snapshots, release branches 3, 2.0, 2, and 1.6, with specific patch dates indicating when the issue was addressed in different release streams. The flaw demonstrates a classic security weakness that can be exploited through improper input validation and arithmetic operations within kernel space code.
The technical implementation of this vulnerability stems from an integer overflow condition that occurs when processing certain system calls that are part of the FreeBSD compatibility interface. When local users execute specific sequences of operations that trigger the compatibility code path, the integer overflow can result in heap corruption or system crashes. This type of flaw falls under CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption and arbitrary code execution. The vulnerability exploits the fundamental weakness in how the system handles integer arithmetic operations, particularly when dealing with large values that exceed the maximum representable value for the target integer type.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable privilege escalation attacks. Local attackers who can successfully exploit this integer overflow can cause system instability through heap corruption, leading to system crashes or kernel panics that effectively result in a denial of service condition. More critically, the vulnerability may allow attackers to gain root privileges, representing a severe escalation of privilege threat. This capability stems from the fact that the flaw exists within kernel space compatibility code, meaning that successful exploitation could provide attackers with the ability to execute arbitrary code with the highest system privileges. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques, specifically targeting kernel-level weaknesses that can be leveraged to gain administrative control over affected systems.
Mitigation strategies for this vulnerability require immediate system updates and patches to address the specific integer overflow condition in the FreeBSD compatibility code. System administrators should prioritize applying the relevant security patches released by NetBSD development team, which were issued on September 13, 2005, for the affected versions and September 14, 2005, for NetBSD-1.6. Additionally, organizations should consider disabling FreeBSD compatibility features if they are not actively required, as this would eliminate the attack surface for this specific vulnerability. Monitoring systems should be configured to detect unusual patterns of system calls or memory allocation behaviors that might indicate exploitation attempts. The vulnerability highlights the importance of thorough input validation and proper integer handling in kernel space code, emphasizing that even compatibility layers must undergo rigorous security testing to prevent exploitation of fundamental arithmetic errors that can compromise entire system security models.