Title       : Security Vulnerability with land on HP-UX
Date        : 980224
Type        : SB
Document ID : HPSBUX9801-076

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**REVISED 02** HEWLETT-PACKARD SECURITY BULLETIN: #00076, 21 January 1998
Last Revised:   23 February 1998
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The information in the following Security Bulletin should be acted upon
as soon as possible.  Hewlett-Packard will not be liable for any
consequences to any customer resulting from customer's failure to fully
implement instructions in this Security Bulletin as soon as possible.

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PROBLEM:  A TCP SYN packet with target host's address as both source and
          destination can cause system hangs.

PLATFORM: HP9000 Series 7/800 running HP-UX releases 9.X, 10.X, and 11.00.

DAMAGE:   Users on the network can cause system hangs.

SOLUTION: Apply patches listed below.

AVAILABILITY:  All patches are available now.
CHANGE SUMMARY: R1 Adds patches for HP-UX release 10.24 (VVOS)
                R2 Adds patches for HP-UX release 10.16 (CMW BLS)
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I.
   A. Background
      CERT Advisory CA-97.28 discusses the widely available "land" program,
      a denial of service tool that is effective against HP-UX systems.
      land sends carefully crafted TCP packets (the source and destination
      are identical).

**REVISED 02**
   B. Fixing the problem
      The problem can be fixed by applying the appropriate cumulative ARPA
      Transport patch mentioned below.

      HP-UX release 11.00 HP9000 Series 700/800     PHNE_14017
      HP-UX release 10.30 HP9000 Series 700/800     PHNE_13671
      HP-UX release 10.20 HP9000 Series 800         PHNE_13468
      HP-UX release 10.24 HP9000 Series 700         PHNE_13888
      HP-UX release 10.24 HP9000 Series 800         PHNE_13889
      HP-UX release 10.20 HP9000 Series 800         PHNE_13468
      HP-UX release 10.20 HP9000 Series 700         PHNE_13469
---->>HP-UX release 10.16 HP9000 Series 700         PHKL_14242
---->>HP-UX release 10.16 HP9000 Series 800         PHKL_14243
      HP-UX release 10.10 HP9000 Series 800         PHNE_13470
      HP-UX release 10.10 HP9000 Series 700         PHNE_13471
      HP-UX release 10.01 HP9000 Series 800         PHNE_13472
      HP-UX release 10.01 HP9000 Series 700         PHNE_13473
      HP-UX release 10.00 HP9000 Series 800         PHNE_13474
      HP-UX release 10.00 HP9000 Series 700         PHNE_13475
      HP-UX release  9.04 HP9000 Series 800         PHNE_13476
      HP-UX release  9.0[3,5,7] HP9000 Series 700   PHNE_13477
      HP-UX release  9.01 HP9000 Series 700         PHNE_13478
      HP-UX release  9.00 HP9000 Series 800         PHNE_13479

   C. Impact of the patch
      The patch changes the implementation of the ISO OSI stack such
      that the host now enforces the rule that inbound packets are never
      from itself - if packets claim otherwise, they are simply dropped.

   D. To subscribe to automatically receive future NEW HP Security
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   F. To report new security vulnerabilities, send email to

          security-alert@hp.com

      Please encrypt any exploit information using the security-alert
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