VIGILANTe advisory 2001003 : Atmel SNMP Non Public Community Stri ng DoS Vulnerability

From: Frederic Brouille (frederic.brouilleat_private)
Date: Fri Dec 21 2001 - 08:49:24 PST

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    Atmel SNMP Non Public Community String DoS Vulnerability
    Advisory Code: VIGILANTE-2001003
    Release Date: December 21, 2001
    
    Systems affected:
    Atmel Firmware 1.3
    Tested on a WAP11 Syslink Wireless Access Point WPC11 Wireless network PC
    card (PCMCIA+PCI) Under Windows 2000
    
    Systems not affected:
    Vendor released a more recent version of this software, but it is not known
    if it is vulnerable to this attack. We did not perform tests on this newer
    version.
    
    The problem:
    During some tests we noticed that the 1.3 version firmware contains a flaw
    that may result in a denial-of-service, preventing any new further request
    to be correctly handled by the device. 
    
    
    If a SNMP read request is made with a community name different than "public"
    ( including NULL community string ) or an unknown OID, it leads to a denial
    of service even if the answer is correct ( ie the returned code error in the
    reply is ok ). Any SNMP request made to the Wireless Access Point is then
    denied. Reset of the appliance is necessary to recover normal functioning. 
    Vendor status:
    Linsys was contacted October 30, 2001 and answered. They say that the 1.3
    firmware for the WAP11 is a somewhat dated release. The current shipping
    version is 1.4g.5.
    
    Vulnerability Assessment:
    A test case to detect this vulnerability was added to SecureScan NX in the
    upgrade package of December 21, 2001. You can see the documentation of this
    test case 15471 on SecureScan NX web site at
    http://securescannx.vigilante.com/tc/15471 
    
    Fix:
    Vendor suggested the following : "for customers that have earlier versions,
    new code is available on our ftp site:
    ftp://ftp.linksys.com/pub/network/wap11fw14g5.exe.
    
    The new utility is also required to use this firmware, also available on our
    ftp site : ftp://ftp.linksys.com/pub/network/wap11sw.exe.
    
    These links are also published on our website at :
    http://www.linksys.com/download/firmware.asp under the wap11 section from
    the drop down." 
    
    CVE:
    Common Vulnerabilities and Exposures group ( reachable at
    http://cve.mitre.org/ ) was contacted to get a candidat number. It will be
    included here when available.
    
    Credit:
    This vulnerability was discovered by Frederic Brouille, member of VIGILANTe.
    We wish to thank Atmel for their help in investigating this problem. 
    
    Copyright VIGILANTe.com, Inc. 2001-12-21
    
    Disclaimer:
    The information within this document may change without notice. Use of this
    information constitutes acceptance for use in an AS IS condition. There are
    NO warranties with regard to this information. In no event shall the author
    be liable for any consequences whatsoever arising out of or in connection
    with the use or spread of this information. Any use of this information lays
    within the user's responsibility.
    
    Feedback:
    Please send suggestions, updates, and comments to isisat_private
    



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