Microsoft Windows 95 and 98 with multiple TCP/IP stacks ICMP packet denial of service

win-multiple-ip-dos (7542) The risk level is classified as MediumMedium Risk


Microsoft Windows 95 and 98 clients with multiple TCP/IP stacks bound to the same MAC address are vulnerable to a denial of service attack. If a remote attacker pings an affected host, the host responds with one ACK packet for each TCP/IP stack loaded on the host. This could create collisions on the subnet, which would disrupt network functionality.


Denial of Service


No remedy available as of September 1, 2014.


  • NTBugTraq Mailing List, Sat, 6 Feb 1999 07:00:32 -0800: New Windows 9x Bug: TCP Chorusing.
  • BID-225: Windows 9x TCP Chorusing Vulnerability
  • CVE-1999-1201: Windows 95 and Windows 98 systems, when configured with multiple TCP/IP stacks bound to the same MAC address, allow remote attackers to cause a denial of service (traffic amplification) via a certain ICMP echo (ping) packet, which causes all stacks to send a ping response, aka TCP Chorusing.
  • OSVDB ID: 218: Microsoft Windows Multiple TCP/IP Stack Malformed Ping DoS

Platforms Affected:

  • Microsoft Windows 95
  • Microsoft Windows 98


Feb 06, 1999

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