CVE-2004-1802 in Chat Anywhere
Summary
by MITRE
Chat Anywhere 2.72 and earlier allows remote attackers to hide their IP address by using %00 before the nickname, which causes the IP address to be displayed as $IP$ on the administration web page.
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Analysis
by VulDB Data Team • 07/16/2017
The vulnerability identified as CVE-2004-1802 affects Chat Anywhere version 2.72 and earlier, representing a significant security flaw in the chat server's handling of user identification and network address management. This issue stems from improper input validation within the nickname processing mechanism, where the application fails to properly sanitize user-supplied data before displaying it in administrative interfaces. The vulnerability specifically exploits the handling of null byte sequences within nickname parameters, creating a vector for IP address obfuscation that undermines the system's ability to accurately track user connections and network activities.
The technical implementation of this vulnerability leverages the null byte character sequence %00 as a payload to manipulate how the chat server processes and displays user information. When a malicious user submits a nickname containing this null byte sequence, the application's parsing logic becomes confused during the display process, resulting in the administrative web interface showing $IP$ instead of the actual IP address. This behavior represents a fundamental flaw in input sanitization and output encoding practices, where the system fails to properly validate or escape special characters before rendering them in web contexts. The vulnerability operates at the intersection of improper input validation and insecure output handling, creating a condition where user-provided data can manipulate the application's display logic.
The operational impact of this vulnerability extends beyond simple IP address obfuscation, as it fundamentally compromises the administrative monitoring capabilities of the chat system. System administrators lose visibility into actual user connections, making it impossible to track legitimate users or identify malicious actors within the network. This weakness creates an environment where attackers can operate anonymously while potentially conducting unauthorized activities such as spamming, harassment, or other malicious behaviors without detection. The vulnerability directly impacts the system's ability to enforce access controls and maintain audit trails, which are critical components of network security and compliance requirements. From an attacker's perspective, this creates a stealth mechanism that bypasses normal identification procedures and undermines the integrity of the chat server's user management system.
The vulnerability aligns with CWE-116, which addresses improper handling of escape sequences and special characters in output processing, and represents a classic case of insecure input handling that enables information disclosure through manipulation of display mechanisms. From an ATT&CK framework perspective, this vulnerability maps to T1071.004 for application layer protocol, specifically targeting communication protocols and user interface rendering. The flaw also connects to T1566, representing social engineering through manipulation of system information, as attackers can exploit this to appear as legitimate users while conducting malicious activities. Organizations relying on Chat Anywhere for communication services face significant risks including potential data breaches, unauthorized access to system resources, and compromised network integrity. The vulnerability's persistence across multiple versions indicates a systemic issue in the application's architecture that requires comprehensive code review and remediation.
Mitigation strategies should focus on implementing robust input validation and sanitization mechanisms that properly handle special characters including null bytes and other control sequences. The application must validate all user input against a strict whitelist of acceptable characters and ensure proper encoding before any display operations. System administrators should implement network monitoring solutions that can detect anomalous connection patterns and IP address inconsistencies. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other applications. The most effective remediation involves updating to a patched version of Chat Anywhere that properly handles input validation and implements proper output encoding. Additionally, organizations should consider implementing network-level monitoring tools that can detect and alert on suspicious traffic patterns that might indicate exploitation of this vulnerability. The fix should also include logging mechanisms that capture and analyze attempts to manipulate the nickname field, providing administrators with visibility into potential exploitation attempts and enabling proactive threat hunting activities.