CVE-2006-4117 in Solaris
Summary
by MITRE
The squeue_drain function in Sun Solaris 10, possibly only when run on CMT processors, allows remote attackers to cause a denial of service ("bad trap" and system panic) by opening and closing a large number of TCP connections ("heavy TCP/IP loads"). NOTE: the original report specifies the function name as "drain_squeue," but this is likely incorrect.
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Analysis
by VulDB Data Team • 07/18/2019
The vulnerability described in CVE-2006-4117 represents a critical denial of service flaw affecting Sun Solaris 10 operating systems, particularly when executed on CMT (Chip Multi-Threading) processors. This issue stems from improper handling of TCP connection management within the kernel's squeue_drain function, which serves as a crucial component in the Solaris networking stack's connection queue processing mechanisms. The flaw manifests when the system experiences heavy TCP/IP loads through rapid opening and closing of numerous TCP connections, creating a scenario where the kernel's trap handling mechanisms become overwhelmed and ultimately result in system panic conditions.
The technical root cause of this vulnerability lies in the insufficient validation and resource management within the squeue_drain function, which is responsible for processing connection queue operations in the Solaris kernel. When subjected to massive TCP connection churn, the function fails to properly handle the trap conditions that occur during connection state transitions, leading to a "bad trap" error condition that triggers a system panic. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, though in this case the overflow occurs in kernel trap handling rather than user-space buffers. The vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication, making it a significant threat to network availability.
The operational impact of this vulnerability extends beyond simple service disruption, as it can cause complete system crashes that require manual intervention to restore normal operations. Attackers can exploit this weakness by establishing and rapidly terminating thousands of TCP connections against a vulnerable Solaris 10 system, effectively overwhelming the kernel's connection handling capabilities. The system panic resulting from this exploitation creates a denial of service condition that can affect critical network services and applications running on the affected system. According to ATT&CK framework reference T1499.004, this vulnerability enables an adversary to perform resource exhaustion attacks, while the underlying mechanism falls under T1070.006 for system and network disruption techniques. The CMT processor dependency suggests that the vulnerability may be more pronounced on systems with specific hardware configurations that enable multi-threading capabilities, though the exact relationship between processor architecture and vulnerability exploitation remains complex.
Mitigation strategies for CVE-2006-4117 should focus on both immediate system hardening and long-term architectural improvements. System administrators should apply the appropriate Sun Microsystems security patches and updates that address the kernel-level flaw in the squeue_drain function. Network-level protections can include implementing connection rate limiting and TCP connection tracking mechanisms to prevent the rapid connection churn that triggers the vulnerability. Additionally, monitoring systems should be configured to detect unusual TCP connection patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper kernel resource management and trap handling, as outlined in the CWE taxonomy under categories related to kernel-level memory corruption and improper resource handling. Organizations should also consider implementing network segmentation and access controls to limit exposure to potential attackers who might attempt to exploit this vulnerability, particularly in environments where Solaris 10 systems remain operational without proper patching.