KPMG-2002017: Snapgear Lite+ Firewall Denial of Service

From: Peter Gründl (pgrundlat_private)
Date: Thu May 02 2002 - 04:56:53 PDT

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    Title: Snapgear Lite+ Firewall Denial of Service
    
    BUG-ID: 2002017
    Released: 02nd May 2002
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    Problem:
    ========
    Several issues with the Snapgear Lite+ Firewall could allow a
    malicious user to cause a Denial of Service situation, where part
    of or all of the Firewall would cease to function.
    
    
    Vulnerable:
    ===========
    - Snapgear Lite+ V1.5.3 (all issues)
    - Snapgear Lite+ V1.5.4 (some issues)
    
    
    Not vulnerable:
    ===============
    - Snapgear Lite+ V1.6.0
    
    
    Product Description:
    ====================
    Quoted from the vendors webpage:
    
    "The SnapGear LITE+ is an ethernet/broadband VPN router, with one
     10/100BaseT WAN port, one 4-port 10/100BaseT switch on the LAN,
     and one serial port that can have a modem attached for narrowband
     fallback to dial-out."
    
    
    Details:
    ========
    There are four general areas in which we found problems with the
    way the Snapgear Firewall handled malicious traffic:
    
    HTTP)
    If external web management had been enabled, creating 50 connections
    to the web port and cycling through them would result in the
    firewall crashing. In V1.5.4 this would only result in web management
    crashing.
    
    PPTP)
    If PPTP had been enabled, creating 50 connections to the PPTP port and
    cycling through them would result in the firewall crashing.
    
    IPSEC)
    Sending a 0 length UDP packet to UDP port 500 would result in IPSEC
    exiting. This would result in IPSEC no longer working. This issue was
    resolved in v1.5.4.
    
    IP-OPTIONS)
    Sending a stream of approx. 7000 packets with malformed IP options
    through the firewall would result in the firewall crashing. This
    stream could be sent from the internal network or externally.
    
    
    Vendor URL:
    ===========
    You can visit the vendors webpage here: http://www.snapgear.com
    
    
    Vendor response:
    ================
    The vendor was contacted about the first issue on the 14th of
    February, 2002 and subsequently on the 7th of March, 2002 about
    the remainding issues. On the 10th of April, 2002 we received a
    beta version of v1.6.0, which corrected the issues. On the 2nd
    of May, 2002 we received notification that V1.6.0 had been
    released.
    
    
    Corrective action:
    ==================
    Install firmware version 1.6.0, which is available here:
    http://www.snapgear.com/downloads.html
    
    
    Authors:
    Andreas Sandor (asandorat_private) & Peter Gründl (pgrundlat_private)
    
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