CVE-2000-0405 in AntiSniff
Summary
by MITRE
Buffer overflow in L0pht AntiSniff allows remote attackers to execute arbitrary commands via a malformed DNS response packet.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/01/2025
The vulnerability identified as CVE-2000-0405 represents a critical buffer overflow flaw within the L0pht AntiSniff network monitoring tool, which was widely used for detecting network intrusions and monitoring suspicious activities. This particular vulnerability resides in the DNS response packet processing functionality of the software, creating a significant security risk that could be exploited by remote attackers to gain unauthorized control over affected systems. The flaw manifests when the application processes malformed DNS response packets, which are typically part of normal network traffic but have been crafted specifically to trigger the buffer overflow condition.
The technical implementation of this vulnerability stems from inadequate input validation within the DNS packet parsing routines of L0pht AntiSniff. When the software receives a DNS response packet containing oversized or malformed data within its resource record fields, the application fails to properly bounds-check the incoming data before copying it into fixed-size buffers. This classic buffer overflow condition occurs because the software assumes that incoming DNS records will not exceed predetermined size limits, without implementing proper validation mechanisms. The flaw is particularly dangerous because DNS traffic is inherently unpredictable and can be easily manipulated by attackers who position themselves within the network path between the target system and DNS servers, making this a prime candidate for man-in-the-middle attacks.
The operational impact of CVE-2000-0405 extends far beyond simple denial of service conditions, as remote attackers can leverage this vulnerability to execute arbitrary commands with the privileges of the user running the L0pht AntiSniff application. This typically translates to system compromise, allowing attackers to gain full control over the affected machine, potentially establishing persistent backdoors, exfiltrating sensitive data, or using the compromised system as a launch point for further attacks within the network. The vulnerability is especially concerning for network security administrators who rely on such tools for monitoring and protection, as exploiting this flaw can effectively neutralize the security measures that the tool is designed to provide, creating a false sense of security while simultaneously providing attackers with elevated privileges.
This vulnerability aligns with CWE-121, which describes the classic stack-based buffer overflow condition, and demonstrates how improper input validation can lead to privilege escalation and remote code execution. From an ATT&CK perspective, this flaw corresponds to techniques involving remote code execution through network protocols, specifically T1059.007 for command and scripting interpreter and T1133 for external remote services. The attack vector follows T1190 for exploit public-facing application patterns, where attackers target network monitoring tools that are accessible from external networks. Organizations should implement immediate mitigations including patching the affected software to version 2.2 or later, which includes proper bounds checking and input validation mechanisms. Network segmentation and firewall rules should be configured to restrict unnecessary DNS traffic, while monitoring systems should be deployed to detect unusual DNS packet patterns that might indicate exploitation attempts. Additionally, the principle of least privilege should be enforced by running the AntiSniff application with minimal required permissions, limiting the potential impact of successful exploitation.