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             AUSCERT External Security Bulletin Redistribution

       ESB-2004.0121 -- Sun Alert Notification - Sun Alert ID: 57496
              Security Vulnerability in the Apache Web Server
                   "mod_alias" and "mod_rewrite" Modules
                             13 February 2004

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                Apache Web Server
Publisher:              Sun Microsystems
Operating System:       Solaris 9
                        Solaris 8
Platform:               SPARC
                        IA-32
Impact:                 Execute Arbitrary Code/Commands
Access Required:        Remote
CVE Names:              CAN-2003-0542

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   DOCUMENT ID: 57496
   SYNOPSIS: Security Vulnerability in the Apache Web Server "mod_alias"
   and "mod_rewrite" Modules
   DETAIL DESCRIPTION:
   
Sun(sm) Alert Notification

     * Sun Alert ID: 57496
     * Synopsis: Security Vulnerability in the Apache Web Server
       "mod_alias" and "mod_rewrite" Modules
     * Category: Security
     * Product: Solaris
     * BugIDs: 4948830
     * Avoidance: Patch
     * State: Committed
     * Date Released: 10-Feb-2004
     * Date Closed:
     * Date Modified:
       
1. Impact

   A local or remote unprivileged user may be able to execute arbitrary
   code with the privileges of the Apache HTTP process on Solaris 8 and
   Solaris 9 systems when running the bundled version of Apache. This is
   due to a buffer overflow in the Apache modules "mod_alias" and
   "mod_rewrite".
   
   This issue is described at the following sites:
   
   The Apache 1.3.29 and the 2.0.48 release announcements:
     * [1]http://www.apache.org/dist/httpd/Announcement.html
     * [2]http://www.apache.org/dist/httpd/Announcement2.html
       
   CAN-2003-0542:
     * [3]http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0542
       
2. Contributing Factors

   This issue can occur in the following releases:
   
   SPARC Platform
     * Solaris 8
     * Solaris 9 without patch 113146-03
       
   x86 Platform
     * Solaris 8
     * Solaris 9 without patch 114145-02
       
   Note 1: A system is only vulnerable to this issue if the Apache web
   server has been configured and is running on the system. The following
   command can be executed to check if the Apache(1M) httpd daemon is
   running on the system:
    $ /usr/bin/ps -ef | grep httpd
    nobody 103892 102307  0   Jan 20 ?        0:27 /usr/apache/bin/httpd


   Note 2: Apache was not bundled with Solaris prior to Solaris 8.
   However, customers who have built and/or installed a vulnerable
   version of Apache on any version of Solaris are at risk. See the
   Apache URL referenced above for information on where to download the
   latest Apache versions which address this issue.
   
   Note 3: This vulnerability involving the Apache "mod_alias" and
   "mod_rewrite" modules is present in Apache web servers versions 1.3
   through 1.3.28 and 2.0 through 2.0.47.
   
   Note 4: To determine the version of Apache installed, the following
   command can be executed:
    $ /usr/apache/bin/httpd -v
    Server version: Apache/1.3.27 (Unix)
    Server built:   Nov  1 2002 16:16:4

3. Symptoms

   There are no reliable symptoms that would show the described issue has
   been exploited to gain unauthorized uid "nobody" access to a host.
   SOLUTION SUMMARY:
   
4. Relief/Workaround

   Some relief to the buffer overflow is available by enabling
   non-executable user stacks (although this does not provide 100 percent
   protection against exploitation of this vulnerability, it makes the
   likelihood of a successful exploit much smaller). This workaround is
   only effective on the following architectures:
     * sun4u
     * sun4m
     * sun4d
       
   Note: This workaround will not work on Intel platforms.
   
   To determine a systems architecture, use the "uname -m" command.
   
   To enable non-executable program stacks add the following lines to the
   "/etc/system" file and reboot the system:
    set noexec_user_stack = 1
    set noexec_user_stack_log = 1

   The above tunable parameters are described in the Solaris Tunable
   Parameters Reference Manual at: [4]http://docs.sun.com.
   
5. Resolution

   This issue is addressed in the following releases:
   
   SPARC Platform
     * Solaris 9 with patch 113146-03 or later
       
   x86 Platform
     * Solaris 9 with patch 114145-02 or later
       
   A final resolution is pending completion.
   
   This Sun Alert notification is being provided to you on an "AS IS"
   basis. This Sun Alert notification may contain information provided by
   third parties. The issues described in this Sun Alert notification may
   or may not impact your system(s). Sun makes no representations,
   warranties, or guarantees as to the information contained herein. ANY
   AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
   WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
   NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT
   YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT,
   INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE
   OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN.
   This Sun Alert notification contains Sun proprietary and confidential
   information. It is being provided to you pursuant to the provisions of
   your agreement to purchase services from Sun, or, if you do not have
   such an agreement, the Sun.com Terms of Use. This Sun Alert
   notification may only be used for the purposes contemplated by these
   agreements.
   
   Copyright 2000-2004 Sun Microsystems, Inc., 4150 Network Circle, Santa
   Clara, CA 95054 U.S.A. All rights reserved.
   

References

   1. http://www.apache.org/dist/httpd/Announcement.html
   2. http://www.apache.org/dist/httpd/Announcement2.html
   3. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0542
   4. http://docs.sun.com/

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