CVE-2007-3923 in Wide Area Application Services
Summary
by MITRE
The Common Internet File System (CIFS) optimization in Cisco Wide Area Application Services (WAAS) 4.0.7 and 4.0.9, as used by Cisco WAE appliance and the NM-WAE-502 network module, when Edge Services are configured, allows remote attackers to cause a denial of service (loss of service) via a flood of TCP SYN packets to port (1) 139 or (2) 445.
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Analysis
by VulDB Data Team • 07/22/2019
The vulnerability identified as CVE-2007-3923 resides within the Common Internet File System optimization implementation of Cisco Wide Area Application Services version 4.0.7 and 4.0.9. This flaw specifically affects Cisco WAE appliances and the NM-WAE-502 network module when Edge Services are configured. The vulnerability manifests as a denial of service condition that can be triggered by remote attackers through the systematic flooding of TCP SYN packets directed at specific network ports. The targeted ports are 139 and 445, which are standard ports used by the CIFS protocol for file sharing and network communication. This represents a critical weakness in the network infrastructure's ability to maintain service availability under attack conditions.
The technical mechanism underlying this vulnerability involves the improper handling of TCP SYN packets within the CIFS optimization layer of the WAAS implementation. When the system receives a high volume of SYN packets on the designated ports, the optimization process fails to properly manage the connection establishment requests, leading to resource exhaustion and service disruption. This behavior aligns with CWE-400, which classifies the vulnerability as a resource exhaustion issue where the system's inability to properly process legitimate connection requests creates a window for denial of service attacks. The flaw essentially allows attackers to consume system resources through a relatively simple attack vector that requires minimal computational overhead while generating significant impact.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire network infrastructure's availability. When an attacker successfully exploits this vulnerability, the affected Cisco WAE appliances or network modules will experience complete loss of service, effectively cutting off file sharing capabilities and network access for applications relying on these services. This vulnerability is particularly concerning because it affects the edge services configuration, which typically handles critical network traffic and serves as a gateway for file sharing operations. The attack requires only the sending of TCP SYN packets, making it accessible to attackers with basic network tools and potentially automated attack frameworks. This characteristic places the vulnerability in the ATT&CK framework under the T1498 technique category, specifically targeting network denial of service through resource exhaustion.
Mitigation strategies for CVE-2007-3923 should focus on implementing network-level protections that can detect and filter malicious TCP SYN packet floods before they reach the vulnerable system. Network administrators should consider deploying rate limiting mechanisms at the perimeter firewalls and implementing SYN cookies or similar TCP stack enhancements to prevent resource exhaustion. Additionally, applying the latest security patches from Cisco that address this specific vulnerability is essential for maintaining system integrity. The solution approach should incorporate both defensive network measures and proactive system updates to ensure that the CIFS optimization layer properly handles connection requests without resource exhaustion. Organizations should also consider network segmentation to isolate vulnerable appliances and implement monitoring systems that can detect unusual traffic patterns indicating potential SYN flood attacks. The vulnerability demonstrates the importance of proper input validation and resource management in network optimization services, particularly when dealing with protocol implementations that handle connection-oriented communication.