Thursday, 12 June 2014

NetScreen Firewall: DNS lookup issue may cause denial of service

Product Affected:

NetScreen Firewalls
Problem:
A Denial of Service (DoS) issue has been found in Juniper Networks NetScreen Firewall products. When encountered, this issue can cause the device to crash and reboot. If an attacker were to repeatedly exploit the issue a sustained denial of service could take place on the device. The issue is not encountered unless a feature is enabled that requires the device to use its built-in DNS lookup client.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

Solution:
 A software update for ScreenOS has been released to resolve this issue. The release containing the fix includes ScreenOS 6.3r17 and subsequent releases

KB16765 - "In which releases are vulnerabilities fixed?" describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.
Workaround:
 There is no workaround for this issue. An upgrade to a fixed version of the software for the fix.

5 comments:

  1. how to know if built-in DNS lookup client is enabled ?

    ReplyDelete
    Replies
    1. Here Are the command to enable DNS Client

      set dns proxy
      set dns proxy enable
      set dns server-select domain * primary-server x.x.x.x secondary-server y.y.y.y tertiary-server z.z.z.z
      set interface ethernet#/# proxy dns

      Delete
    2. Thanks,,,

      So... essentially

      If...
      (M)-> get dns proxy
      dns proxy not started

      AND / OR

      (M)-> get dns ddns
      ddns client not started

      If the above is true we do not need to patch our firewalls? Please clarify.

      Warm regards

      Delete
    3. If you did not start your DNS client then you not need to patch your Netscreen now. However advisable to upgrade to latest screen OS once is available.

      Delete
    4. Thank you Sire!

      Delete

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