Cisco VPN 3000 series concentrators Windows PPTP client denial of service

cisco-vpn-pptp-dos (10021) The risk level is classified as MediumMedium Risk


Cisco VPN 3000 series concentrators are vulnerable to a denial of service attack, caused by a vulnerability that occurs when handling requests from Windows Point-to-Point Tunneling Protocol (PPTP) clients. If a remote attacker using a Windows PPTP client with the "No Encryption" option set connects to an affected concentrator using "Encryption", the attacker could cause the concentrator to reload.


Denial of Service


Upgrade to the latest software version for your device (3.6(Rel) or later), (3.5(Rel) or later), (3.1(Rel) or later), (3.0(Rel) or later), (2.5.2(F) or later), as listed in Cisco Security Advisory: Cisco VPN 3000 Concentrator Multiple Vulnerabilities. See References.


  • CIAC Information Bulletin M-119: Cisco VPN Concentrators and VPN 3002 Client Multiple Vulnerabilities.
  • vpn3k-multiple-vuln-pub: Cisco Security Advisory: Cisco VPN 3000 Concentrator Multiple Vulnerabilities.
  • BID-5609: Multiple Cisco VPN 3000 Vulnerabilities
  • BID-5625: Cisco VPN Concentrator PPTP Client Remote Denial Of Service Vulnerability
  • CVE-2002-1095: Cisco VPN 3000 Concentrator before 2.5.2(F), with encryption enabled, allows remote attackers to cause a denial of service (reload) via a Windows-based PPTP client with the No Encryption option set.
  • OSVDB ID: 8910: Cisco VPN 3000 Concentrator PPTP No Encryption Option Remote DoS

Platforms Affected:

  • Cisco Secure Access Control Server 2.6.3
  • Cisco VPN 3000 Concentrator 2.0
  • Cisco VPN 3000 Concentrator 2.5.2.A
  • Cisco VPN 3000 Concentrator 2.5.2.B
  • Cisco VPN 3000 Concentrator 2.5.2.C
  • Cisco VPN 3000 Concentrator 2.5.2.D
  • Cisco VPN 3002 Hardware Client


Sep 03, 2002

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