CVE-2001-1184 in Winsock RSHD-NT
Summary
by MITRE
wrshdsp.exe in Denicomp Winsock RSHD/NT 2.21.00 and earlier allows remote attackers to cause a denial of service (CPU consumption) via (1) in 2.20.00 and earlier, an invalid port number such as a negative number, which causes a connection attempt to that port and all ports below 1024, and (2) in 2.21.00, a port number of 1024.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2001-1184 affects the wrshdsp.exe component within Denicomp Winsock RSHD/NT version 2.21.00 and earlier implementations. This service operates as a remote shell daemon that provides remote execution capabilities over network connections, making it a critical component in network infrastructure deployments. The flaw manifests in how the service handles malformed port number inputs during connection processing, creating a significant security risk that can be exploited by remote attackers to disrupt system operations.
The technical implementation of this vulnerability stems from inadequate input validation within the wrshdsp.exe process. In version 2.20.00 and earlier, when an attacker provides a negative port number as input, the service fails to properly validate this input and instead attempts to establish connections to the specified negative port number along with all ports below 1024. This creates an exponential CPU consumption pattern as the system attempts to process connection attempts to numerous port numbers simultaneously. In version 2.21.00, the vulnerability manifests differently with a specific port number of 1024 being processed in a manner that causes similar resource exhaustion behavior. The flaw represents a classic case of improper input validation and error handling that can be categorized under CWE-20, which addresses improper input validation in software implementations.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise system availability and performance. When exploited, the vulnerability causes sustained high CPU utilization that can render the affected system unusable for legitimate users while consuming significant system resources. This type of attack aligns with ATT&CK technique T1498, which describes denial of service attacks that consume system resources. The vulnerability affects the availability aspect of the CIA triad by preventing legitimate users from accessing the service while potentially causing system instability. Network administrators may observe unusual CPU spikes and system performance degradation that could be misinterpreted as legitimate high-traffic conditions, delaying detection of the actual attack.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected Denicomp Winsock RSHD/NT implementation to version 2.21.01 or later, which contains the necessary fixes for the port validation logic. System administrators should implement network-level controls to restrict access to the RSHD service ports, particularly limiting connectivity to trusted sources only. Additional protective measures include monitoring for unusual CPU consumption patterns and implementing intrusion detection systems that can identify malformed port number attempts. The vulnerability demonstrates the importance of proper input validation and error handling in network services, aligning with security best practices outlined in NIST SP 800-144 and ISO/IEC 27001 standards for secure system development and operation. Organizations should also consider implementing network segmentation to limit the potential impact of such vulnerabilities and ensure that critical services are not directly exposed to untrusted network segments.