CVE-1999-1278 in Nlog
Summary
by MITRE
nlog CGI scripts do not properly filter shell metacharacters from the IP address argument, which could allow remote attackers to execute certain commands via (1) nlog-smb.pl or (2) rpc-nlog.pl.
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Analysis
by VulDB Data Team • 10/20/2025
The vulnerability described in CVE-1999-1278 represents a classic command injection flaw in network logging utilities that was prevalent during the late 1990s era of internet infrastructure. This issue affects nlog CGI scripts which are designed to process network logging data and typically operate in server environments where they receive input from various network sources. The vulnerability specifically targets the handling of IP address arguments within these scripts, demonstrating a fundamental lack of proper input validation and sanitization that was common in early web applications and network utilities of that period.
The technical flaw manifests when nlog CGI scripts fail to properly filter or escape shell metacharacters from the IP address argument that they receive. This occurs because the scripts directly incorporate user-supplied IP address data into shell commands without adequate sanitization, creating an environment where malicious actors can inject arbitrary shell commands through carefully crafted IP address inputs. The vulnerability affects two specific scripts: nlog-smb.pl and rpc-nlog.pl, which are typically used for processing smb and rpc network logging data respectively. These scripts are particularly dangerous because they often run with elevated privileges, allowing the executed commands to operate at higher permission levels than normal user accounts.
The operational impact of this vulnerability is significant as it enables remote attackers to execute arbitrary commands on the affected system without requiring authentication or direct access. Attackers can leverage this weakness to perform various malicious activities including but not limited to executing shell commands, accessing sensitive system files, modifying system configurations, or even establishing persistent backdoors. The vulnerability is particularly concerning because it can be exploited remotely over the network, making it accessible to attackers anywhere on the internet. This type of vulnerability falls under the CWE-77 category of command injection, which is classified as a critical security weakness that has been consistently identified in security assessments and penetration testing throughout the history of web application security.
The exploitation of this vulnerability demonstrates the importance of input validation and proper sanitization practices in network applications, particularly those that interact with operating system commands. Organizations using these nlog scripts would have been vulnerable to attacks that could lead to complete system compromise, data theft, or service disruption. The vulnerability also highlights the risks associated with legacy network infrastructure and the importance of maintaining up-to-date security practices even for older systems. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command and control communications, privilege escalation, and execution of malicious code through legitimate system processes, making it a critical target for both defensive and offensive security operations.
Mitigation strategies for this vulnerability include implementing proper input validation and sanitization of all user-supplied data, particularly when that data is used in shell command execution contexts. The most effective remediation involves rewriting the affected scripts to properly escape or filter shell metacharacters from all input parameters, or alternatively using safer programming practices that avoid direct shell command execution. Organizations should also implement network segmentation and access controls to limit exposure of these vulnerable scripts, along with regular security audits and vulnerability assessments to identify similar weaknesses in other legacy systems. The vulnerability serves as a historical example of why modern security practices emphasize the principle of least privilege and the importance of treating all user input as potentially malicious in nature.