CVE-2006-3840 in RealSecure
Summary
by MITRE
The SMB Mailslot parsing functionality in PAM in multiple ISS products with XPU (24.39/1.78/epj/x.x.x.1780), including Proventia A, G, M, Server, and Desktop, BlackICE PC and Server Protection 3.6, and RealSecure 7.0, allows remote attackers to cause a denial of service (infinite loop) via a crafted SMB packet that is not properly handled by the SMB_Mailslot_Heap_Overflow decode.
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Analysis
by VulDB Data Team • 06/24/2019
The vulnerability described in CVE-2006-3840 represents a critical denial of service weakness within the SMB Mailslot parsing mechanisms of multiple Intrusion Detection System (IDS) products from ISS. This flaw specifically affects versions of ISS products that incorporate XPU (eXtensible Processing Unit) components with version identifiers including 24.39/1.78/epj/x.x.x.1780. The affected systems include Proventia A, G, M, Server, and Desktop products, along with BlackICE PC and Server Protection 3.6, and RealSecure 7.0. These products are designed to monitor and analyze network traffic for security threats, making their stability and reliability crucial for network defense operations.
The technical flaw manifests in the improper handling of SMB (Server Message Block) packets during the SMB_Mailslot_Heap_Overflow decode process. When a specially crafted SMB packet is received by the vulnerable systems, the parsing functionality enters an infinite loop condition that consumes excessive system resources and ultimately causes the service to become unresponsive. This behavior represents a classic denial of service vulnerability where the attacker can disrupt legitimate network operations without requiring authentication or privileged access. The vulnerability specifically targets the heap management operations within the SMB mailslot processing code, which is part of the broader SMB protocol implementation used for inter-process communication and network file sharing.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the core functionality of intrusion detection systems that are critical for network security monitoring. Organizations relying on these ISS products for security operations would experience complete loss of detection capabilities when the vulnerable systems become unresponsive due to the infinite loop condition. This creates a significant security gap where network traffic could flow unmonitored, potentially allowing malicious activities to go undetected. The vulnerability demonstrates how seemingly minor parsing flaws in network protocol handling can result in catastrophic service failures, particularly in security-critical infrastructure components where availability is as important as confidentiality and integrity.
The root cause of this vulnerability aligns with CWE-838, which addresses improper handling of data structures and memory management issues in network protocols. This weakness enables attackers to manipulate system resources through carefully crafted network packets, potentially leading to complete system compromise or denial of service across the entire network monitoring infrastructure. Mitigation strategies should include immediate patch deployment for all affected ISS products, network segmentation to isolate vulnerable systems, and implementation of network monitoring to detect anomalous SMB traffic patterns. Additionally, organizations should consider implementing redundant monitoring systems and establishing incident response procedures to handle potential service disruptions. The vulnerability highlights the importance of proper input validation and robust error handling in security software, as well as the need for comprehensive testing of protocol parsing functions in network security appliances. This issue also relates to ATT&CK technique T1499.004, which covers network disruption through resource exhaustion, demonstrating how such vulnerabilities can be exploited to create availability issues in security infrastructure components.