CVE-2011-2208 in Linux
Summary
by MITRE
Integer signedness error in the osf_getdomainname function in arch/alpha/kernel/osf_sys.c in the Linux kernel before 2.6.39.4 on the Alpha platform allows local users to obtain sensitive information from kernel memory via a crafted call.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability identified as CVE-2011-2208 represents a critical integer signedness error within the Linux kernel's Alpha platform implementation, specifically affecting the osf_getdomainname function located in arch/alpha/kernel/osf_sys.c. This flaw exists in kernel versions prior to 2.6.39.4 and demonstrates a classic security issue where improper handling of signed and unsigned integer values creates exploitable conditions that can lead to information disclosure. The vulnerability is classified under CWE-194, which deals with the use of a signed integer where an unsigned value is expected, creating potential for unexpected behavior in boundary conditions and memory access patterns.
The technical implementation of this vulnerability stems from how the osf_getdomainname function processes domain name length parameters, where a signed integer variable is used in a context that expects unsigned values. When local users craft specific system calls with manipulated parameters, the signedness error causes the kernel to interpret memory addresses or buffer sizes incorrectly, leading to unintended memory access patterns. This misinterpretation allows attackers to read kernel memory contents that should remain protected, as the signed integer overflow or underflow conditions enable access to memory regions beyond the intended boundaries of the domain name buffer. The flaw operates at the kernel level and requires local system access, making it a local privilege escalation vulnerability that can be exploited by users with minimal privileges to gain access to sensitive kernel data.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked kernel memory can contain sensitive data including cryptographic keys, passwords, session tokens, and other confidential information that could be leveraged for further attacks. Attackers can potentially use this information to craft more sophisticated exploits or to bypass security mechanisms within the kernel. The vulnerability affects systems running Linux kernel versions up to 2.6.39.3 on Alpha architecture platforms, which were commonly used in high-performance computing environments and certain enterprise systems. This creates a significant risk for organizations maintaining legacy Alpha-based systems where patching may be delayed or complex due to hardware dependencies and system architecture constraints.
Mitigation strategies for this vulnerability primarily involve applying the official kernel patches released by the Linux kernel security team, specifically updating to kernel version 2.6.39.4 or later where the signedness error has been corrected. System administrators should also implement additional security measures such as restricting local user access to minimize potential exploitation vectors, monitoring system calls for suspicious patterns, and ensuring that Alpha-based systems are properly maintained and updated according to security best practices. The vulnerability demonstrates the importance of proper integer type handling in kernel code and highlights the need for comprehensive code reviews focusing on signedness and unsignedness considerations, particularly in security-critical functions that handle user input or system parameters. Organizations should also consider implementing kernel hardening techniques and runtime protections to reduce the attack surface and limit the potential impact of similar vulnerabilities that may exist in other kernel subsystems.