CVE-2008-4609 in Solaris
Summary
by MITRE
The TCP implementation in (1) Linux, (2) platforms based on BSD Unix, (3) Microsoft Windows, (4) Cisco products, and probably other operating systems allows remote attackers to cause a denial of service (connection queue exhaustion) via multiple vectors that manipulate information in the TCP state table, as demonstrated by sockstress.
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Analysis
by VulDB Data Team • 08/20/2019
The vulnerability described in CVE-2008-4609 represents a critical weakness in the Transmission Control Protocol implementation across multiple operating systems and network devices. This flaw specifically targets the TCP state table management mechanisms that track active connections and their associated states during network communication. The vulnerability enables remote attackers to exploit the connection queue handling process through various manipulation vectors that directly impact how TCP state information is maintained and processed. The issue manifests as a denial of service condition where legitimate network connections become impossible to establish due to exhaustion of available connection slots in the system's TCP connection queue.
The technical implementation of this vulnerability stems from insufficient validation and handling of TCP state transitions within the connection tracking mechanisms of affected systems. Attackers can leverage this weakness by sending specially crafted TCP packets that manipulate the state table entries in ways that cause the system to allocate resources for connections that either never complete or remain in incomplete states for extended periods. This manipulation typically involves initiating multiple half-open connections or exploiting race conditions in state table updates that allow attackers to consume connection slots faster than the system can process legitimate connections. The sockstress attack demonstrated in this vulnerability exploits these weaknesses by creating a high volume of connection attempts that flood the TCP state table, ultimately exhausting available resources and preventing new legitimate connections from being established.
The operational impact of CVE-2008-4609 is severe and affects a broad range of network infrastructure components including servers, routers, firewalls, and other network devices that rely on TCP for communication. Organizations running affected systems experience complete service disruption where network services become unavailable to legitimate users while attackers can maintain persistent denial of service conditions without requiring significant computational resources. This vulnerability particularly affects systems that handle high volumes of incoming connections or those with limited connection queue capacity, making it especially dangerous for web servers, database servers, and network infrastructure devices that must maintain numerous concurrent connections. The impact extends beyond simple service interruption to potentially compromise the availability of critical business applications and services that depend on stable network connectivity.
Mitigation strategies for this vulnerability require immediate implementation of connection rate limiting mechanisms, TCP stack parameter tuning, and network-level filtering to prevent exploitation attempts. System administrators should implement proper TCP connection queue management by adjusting kernel parameters such as net.core.somaxconn and tcp_max_orphans to limit the number of connections that can be queued or held in incomplete states. Network security measures including firewall rules that limit connection attempts from specific source addresses and intrusion detection systems that monitor for suspicious TCP patterns can help detect and prevent exploitation attempts. Additionally, implementing proper TCP stack hardening measures such as disabling unnecessary TCP features, configuring appropriate timeouts for connection states, and applying vendor-specific patches or updates that address the underlying state table management issues. This vulnerability aligns with CWE-129 and CWE-131 categories related to improper input validation and buffer overflow conditions, and maps to ATT&CK techniques involving resource exhaustion and service disruption attacks that target network infrastructure components.