CVE-2007-2434 in Aventail Connect
Summary
by MITRE
Buffer overflow in asnsp.dll in Aventail Connect 4.1.2.13 allows remote attackers to cause a denial of service (application crash) or execute arbitrary code via a malformed DNS query.
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Analysis
by VulDB Data Team • 03/26/2019
The vulnerability identified as CVE-2007-2434 represents a critical buffer overflow flaw within the asnsp.dll component of Aventail Connect version 4.1.2.13. This software serves as a secure remote access solution that enables remote users to connect to corporate networks through virtual private network connections. The buffer overflow occurs specifically when processing DNS queries, making it particularly dangerous as DNS is a fundamental network protocol used extensively across enterprise environments. The flaw resides in the application's handling of malformed DNS query data, where insufficient input validation leads to memory corruption that can be exploited by remote attackers.
The technical implementation of this vulnerability demonstrates a classic buffer overflow condition where the asnsp.dll module fails to properly validate the length of incoming DNS query data before copying it into fixed-size memory buffers. This allows attackers to craft specially malformed DNS queries that exceed the allocated buffer space, resulting in memory corruption that can be leveraged to either crash the application or potentially execute arbitrary code with the privileges of the affected service. The vulnerability's remote exploitability means that attackers do not need physical access to the system or local network privileges to carry out attacks, making it particularly concerning for enterprise environments where such services are exposed to external networks.
From an operational perspective, the impact of this vulnerability extends beyond simple denial of service conditions to potentially enable full system compromise. When exploited successfully, the buffer overflow can cause the Aventail Connect service to crash, leading to service disruption for legitimate users attempting to establish secure connections. However, the more severe implication involves potential code execution capabilities that could allow attackers to gain unauthorized access to the affected system, potentially escalating privileges to system level access. This makes the vulnerability particularly attractive to threat actors targeting enterprise networks where secure remote access solutions are commonly deployed.
The vulnerability aligns with CWE-121, which categorizes buffer overflow conditions as a fundamental weakness in software design that occurs when data is copied into a buffer without proper bounds checking. The attack pattern described in the MITRE ATT&CK framework would fall under the T1203 technique for "Exploitation for Client Execution" where remote attackers leverage service vulnerabilities to execute malicious code. Organizations using Aventail Connect 4.1.2.13 should prioritize immediate patching or mitigation strategies, as the vulnerability affects core network infrastructure components that are essential for remote workforce connectivity. The flaw's potential for remote code execution makes it a high-priority target for exploitation by both nation-state actors and cybercriminal organizations seeking to establish persistent access to enterprise networks.
Mitigation strategies should include immediate deployment of vendor patches or updates to the Aventail Connect software, along with network segmentation to limit exposure of the vulnerable service to external networks. Organizations should also implement monitoring for anomalous DNS query patterns that might indicate exploitation attempts, while considering temporary network restrictions on DNS traffic to the affected system. The vulnerability demonstrates the importance of proper input validation and memory management practices in network services, highlighting the need for regular security assessments and vulnerability management programs to identify and remediate similar issues before they can be exploited in the wild.