CVE-2001-0877 in Windows
Summary
by MITRE
Universal Plug and Play (UPnP) on Windows 98, 98SE, ME, and XP allows remote attackers to cause a denial of service via (1) a spoofed SSDP advertisement that causes the client to connect to a service on another machine that generates a large amount of traffic (e.g., chargen), or (2) via a spoofed SSDP announcement to broadcast or multicast addresses, which could cause all UPnP clients to send traffic to a single target system.
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Analysis
by VulDB Data Team • 10/01/2025
The vulnerability described in CVE-2001-0877 represents a significant weakness in the Universal Plug and Play implementation across multiple Windows operating systems including Windows 98, 98SE, ME, and XP. This flaw specifically targets the Simple Service Discovery Protocol component of UPnP which is responsible for enabling devices to discover and communicate with each other on a network without requiring manual configuration. The vulnerability stems from insufficient validation of incoming SSDP (Simple Service Discovery Protocol) messages, creating opportunities for malicious actors to exploit the protocol's trust-based architecture.
The technical exploitation of this vulnerability occurs through two primary attack vectors that leverage the inherent design of UPnP's discovery mechanism. The first vector involves spoofing SSDP advertisements that trick UPnP clients into connecting to malicious services on different machines, particularly those configured to generate excessive network traffic such as chargen services. This creates a scenario where legitimate network resources become overwhelmed by traffic generated from the spoofed connections. The second attack vector utilizes spoofed SSDP announcements sent to broadcast or multicast addresses, which can cause all UPnP clients within the network segment to simultaneously direct traffic toward a single target system, effectively creating a distributed denial of service condition against that specific host.
From an operational impact perspective, this vulnerability compromises the availability and stability of networked systems by enabling remote attackers to disrupt normal network operations through legitimate UPnP client behavior. The attack can result in significant network congestion, system resource exhaustion, and complete service unavailability for affected devices. The vulnerability is particularly concerning because it leverages the automatic discovery capabilities that users expect to function seamlessly, making it difficult to detect and prevent. Network administrators may not immediately recognize that their systems are being targeted since the malicious activity appears to originate from legitimate UPnP client processes.
The underlying architectural flaw in UPnP implementations aligns with CWE-20, which addresses "Improper Input Validation," and demonstrates how trust-based protocols can be exploited when proper validation mechanisms are absent. This vulnerability also maps to several ATT&CK techniques including T1498, which covers "Network Denial of Service," and T1071.004, which involves "Application Layer Protocol: DNS." The attack methodology exploits the fundamental assumption that network discovery protocols can be trusted without sufficient verification, creating a pathway for attackers to manipulate network behavior through legitimate system functions.
Mitigation strategies for this vulnerability should focus on network-level protections including implementing firewall rules that restrict SSDP traffic to trusted sources, disabling UPnP functionality when not required, and monitoring network traffic for unusual patterns of broadcast or multicast activity. Network segmentation can help contain the impact of such attacks by limiting the scope of affected systems. System administrators should also consider implementing rate limiting mechanisms on network services that might be targeted by this attack, and regularly updating network monitoring tools to detect anomalous UPnP behavior. The most effective long-term solution involves disabling UPnP entirely on systems where it is not essential, as the protocol's design inherently creates these types of security vulnerabilities that are difficult to fully address through patching alone.