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Forescout NAC ICMP and ARP Protocols Not Filtered Vulnerability Advisory


Forescout NAC (Network Access Control) device does not filter ICMP and ARP packets from unauthorised devices.

  • CVE number: CVE-2012-4985
  • Impact: Medium
  • Vendor homepage:
  • Vendor notified: 21/09/2012
  • Vendor response: This is as per the design of the device.
  • Credit: Joseph Sheridan of ReactionIS

Affected Products

Forescout CounterACT NAC other versions may also be affected.


Forescout NAC (Network Access Control) device is vulnerable to ICMP and ARP protocol filter bypass. The NAC does not filter traffic from unknown clients over these protocols. An attacker with an unauthorised device can engage ARP poisoning attacks and potentially gain access to cleartext login credentials traversing the network (where cleartext protocols are employed). The attacker could then use these credentials via an authorised terminal/workstation to gain full access to the network.


An attacker with an unauthorised device may be able to attack the network using ICMP and ARP protocols.


No known fix available at this time.

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Reaction Information Security is a leading independent pen test consultancy specialising in delivering the highest quality security testing services including network pen testing and web application security testing. As a CESG CHECK Service Provider we are authorised to carry out penetration testing on classified government networks.

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