CVE-2004-1684 in ZyNOS
Summary
by MITRE
Zyxel P681 running ZyNOS Vt020225a contains portions of memory in an ARP request, which allows remote attackers to obtain sensitive information by sniffing the network.
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Analysis
by VulDB Data Team • 06/21/2018
The vulnerability identified as CVE-2004-1684 affects Zyxel P681 broadband routers running ZyNOS firmware version Vt020225a. This security flaw resides in the router's implementation of the Address Resolution Protocol which is fundamental to network communication. The vulnerability specifically manifests in how the router handles ARP requests, creating a situation where sensitive memory contents are inadvertently exposed during network traffic transmission. The issue represents a classic information disclosure vulnerability that can be exploited through passive network monitoring techniques.
The technical flaw stems from improper memory handling within the ARP request processing mechanism of the ZyNOS operating system. When the router receives or generates ARP requests, certain portions of memory containing sensitive data are not properly sanitized or cleared before being transmitted over the network. This memory leakage occurs because the firmware fails to properly isolate or protect sensitive information during the ARP protocol execution phase. The vulnerability is particularly concerning because ARP requests are routinely transmitted across networks and are easily accessible to any network observer with basic packet sniffing capabilities.
From an operational impact perspective, this vulnerability allows remote attackers to conduct passive information gathering without requiring any active exploitation or authentication. An attacker positioned on the same network segment can simply capture ARP traffic using standard network sniffing tools such as tcpdump or wireshark to extract sensitive memory contents. The exposed information may include system configuration details, network credentials, or other confidential data that could be leveraged for further attacks. This represents a significant risk to network security as it provides attackers with valuable intelligence that could facilitate more sophisticated attacks against the affected network infrastructure.
The vulnerability aligns with CWE-200, which describes "Information Exposure," and demonstrates characteristics consistent with the ATT&CK technique T1046 for network service scanning and T1083 for file and directory discovery. The exposure of memory contents through ARP requests creates a pathway for attackers to gather system intelligence that could be used to map network topology, identify vulnerable services, or extract credentials. This type of vulnerability is particularly dangerous because it operates at the network protocol level and can be exploited by anyone with network access, making it a prime target for reconnaissance activities. Organizations should consider implementing network segmentation and monitoring to detect unusual ARP traffic patterns that might indicate exploitation attempts.
Mitigation strategies should include firmware updates from Zyxel if available, network segmentation to limit the attack surface, and implementation of network monitoring solutions that can detect anomalous ARP traffic patterns. Additionally, organizations should consider deploying network access control measures and regularly auditing their network infrastructure for similar memory exposure vulnerabilities. The vulnerability highlights the importance of proper memory management in embedded systems and underscores the need for comprehensive security testing of network equipment firmware to prevent such information disclosure scenarios.