CVE-2002-1403 in dhcpcd
Summary
by MITRE
dhcpcd DHCP client daemon 1.3.22 and earlier allows local users to execute arbitrary code via shell metacharacters that are fed from a dhcpd .info script into a .exe script.
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Analysis
by VulDB Data Team • 05/05/2019
The vulnerability identified as CVE-2002-1403 resides within the dhcpcd DHCP client daemon version 1.3.22 and earlier, representing a critical security flaw that enables local users to execute arbitrary code through carefully crafted shell metacharacters. This issue specifically manifests when the dhcpcd daemon processes information from a dhcpd .info script and subsequently feeds this data into a .exe script without proper sanitization or input validation. The vulnerability stems from inadequate handling of user-supplied data within the daemon's execution flow, creating a potential code injection vector that can be exploited by malicious local users.
The technical implementation of this vulnerability involves the improper handling of shell metacharacters within the dhcpcd daemon's processing pipeline. When the daemon encounters a .info script containing malicious shell metacharacters, these characters are not properly escaped or sanitized before being passed to the .exe script execution context. This allows attackers to inject and execute arbitrary commands with the privileges of the dhcpcd process, which typically runs with elevated permissions to manage network configuration. The vulnerability is classified under CWE-78 as "Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')", which is a well-documented weakness in software systems that handle user input through shell commands.
The operational impact of this vulnerability is significant as it provides local attackers with the ability to execute arbitrary code on systems running vulnerable versions of dhcpcd. This can lead to privilege escalation, system compromise, and potential lateral movement within network environments where the daemon is actively used for DHCP client management. Attackers could leverage this vulnerability to install backdoors, modify network configurations, or gain unauthorized access to sensitive system resources. The attack requires local system access but can be particularly dangerous in environments where dhcpcd is used with elevated privileges, potentially allowing attackers to establish persistent access or escalate their privileges to root level.
Mitigation strategies for CVE-2002-1403 should prioritize immediate patching of affected systems with updated versions of dhcpcd that properly sanitize input data before executing shell commands. Organizations should also implement strict input validation and sanitization measures within their DHCP client configurations, ensuring that all data from .info scripts undergoes proper escaping or filtering before being processed. Network administrators should consider implementing additional security controls such as restricting local user access to systems running dhcpcd, monitoring for suspicious command execution patterns, and maintaining regular security audits of network configuration management tools. The vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, highlighting the need for comprehensive security measures to prevent local privilege escalation through shell injection vulnerabilities. System hardening practices should include limiting the execution privileges of dhcpcd and ensuring that all network configuration scripts are properly validated and sanitized to prevent unauthorized command execution.