CVE-2009-3937 in OpenSolaris
Summary
by MITRE
Memory leak in Solaris TCP sockets in Sun OpenSolaris snv_106 through snv_126 allows local users to cause a denial of service (kernel memory consumption) via unspecified vectors involving tcp_sendmsg processing "ancillary data."
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Analysis
by VulDB Data Team • 01/23/2019
The vulnerability identified as CVE-2009-3937 represents a critical memory management flaw within the Solaris operating system's TCP socket implementation. This issue affects Sun OpenSolaris versions ranging from snv_106 through snv_126, where a memory leak occurs during the processing of TCP send messages containing ancillary data. The flaw resides in the kernel-level TCP stack implementation, specifically within the tcp_sendmsg function which handles the transmission of data messages through TCP sockets. The memory leak manifests when the system processes ancillary data structures that accompany TCP messages, leading to progressive consumption of kernel memory resources without proper deallocation.
The technical nature of this vulnerability stems from improper memory management within the TCP socket subsystem where allocated memory blocks containing ancillary data are not correctly freed during the message processing lifecycle. This memory leak occurs during the tcp_sendmsg function execution when handling socket options and control information that accompanies TCP data transfers. The flaw is particularly concerning because it operates at the kernel level, making it difficult to detect and exploit through normal user-space applications. The vulnerability allows local attackers to repeatedly trigger the memory leak condition through crafted TCP socket operations, causing gradual depletion of available kernel memory.
The operational impact of this vulnerability extends beyond simple resource exhaustion, as it creates a persistent denial of service condition that can severely degrade system performance or cause complete system instability. When the kernel memory consumption reaches critical levels, the system may experience significant performance degradation, application crashes, or even complete system hang conditions. The local nature of the exploit means that any user with access to the system can potentially trigger this vulnerability, making it particularly dangerous in multi-user environments where privilege escalation is not required. The memory leak affects the TCP socket subsystem's ability to maintain proper connection states and handle new connections, ultimately leading to a cascading failure that impacts network services and overall system availability.
Mitigation strategies for CVE-2009-3937 should focus on both immediate patching and operational monitoring approaches. System administrators should prioritize applying the official Solaris patches released by Oracle to address the memory leak in the TCP socket implementation. Additionally, implementing memory monitoring solutions that track kernel memory consumption patterns can help detect early signs of the vulnerability exploitation. Network administrators should consider implementing connection rate limiting and monitoring for unusual socket activity patterns that may indicate exploitation attempts. From a security framework perspective, this vulnerability aligns with CWE-401, which addresses improper handling of memory allocation and deallocation, and maps to ATT&CK technique T1499.002 for network denial of service attacks. The vulnerability demonstrates the importance of proper resource management in kernel-level code and underscores the need for comprehensive testing of system components under stress conditions to prevent similar memory leak scenarios. Organizations should also implement regular system audits to identify potential memory consumption anomalies that could indicate exploitation of this or similar vulnerabilities.