CVE-2002-0382 in XChat
Summary
by MITRE
XChat IRC client allows remote attackers to execute arbitrary commands via a /dns command on a host whose DNS reverse lookup contains shell metacharacters.
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Analysis
by VulDB Data Team • 09/18/2025
The CVE-2002-0382 vulnerability represents a critical command injection flaw in the XChat IRC client that emerged during a period when internet chat applications were rapidly expanding in both corporate and personal environments. This vulnerability specifically targets the client's handling of DNS reverse lookups, exploiting a fundamental security gap in how the application processes network information during connection establishment. The issue manifests when the XChat client executes a /dns command against a host where the reverse DNS lookup resolves to a hostname containing shell metacharacters, creating an exploitable condition that allows remote attackers to inject and execute arbitrary commands on the victim's system.
The technical flaw resides in the improper sanitization and execution of DNS reverse lookup results within the XChat client's command processing pipeline. When a user connects to an IRC server or attempts to resolve a hostname through the /dns command, the client performs a reverse DNS lookup to obtain the hostname associated with the IP address. However, the application fails to properly escape or sanitize the resulting hostname string before incorporating it into shell commands or executing system calls. This vulnerability directly maps to CWE-78, which describes improper neutralization of special elements used in OS commands, making it a classic command injection vulnerability. The flaw operates at the application layer where user-supplied data from network responses is directly consumed without adequate input validation or sanitization, creating a pathway for malicious command execution.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows remote attackers to execute arbitrary commands with the privileges of the user running the XChat client. This could result in complete system compromise, data exfiltration, or the establishment of persistent backdoors within network environments where IRC clients are actively used. The vulnerability is particularly dangerous in corporate settings where employees might be connected to IRC networks for collaboration or information sharing, as attackers could exploit this weakness to gain unauthorized access to internal systems. The attack vector requires minimal interaction from the victim, as simply connecting to an IRC network or using the /dns command against a malicious host is sufficient to trigger the exploit, making it highly effective in automated attack scenarios.
Mitigation strategies for CVE-2002-0382 should focus on immediate application patching, as the vulnerability represents a fundamental flaw in the XChat client's input handling that cannot be effectively addressed through network-level controls alone. System administrators should implement strict network segmentation to limit IRC client access to trusted networks and consider disabling the /dns command functionality within IRC clients when possible. The vulnerability demonstrates the importance of secure coding practices, particularly around input validation and command execution, aligning with ATT&CK technique T1059.007 for command and scripting interpreter. Organizations should also consider implementing network monitoring to detect unusual DNS lookup patterns and shell command executions that might indicate exploitation attempts. Additionally, regular security assessments of legacy applications and the implementation of proper input sanitization routines can prevent similar vulnerabilities from emerging in other software components, emphasizing the need for robust software security practices throughout the development lifecycle.