SGI Information for VU#944335

Apache web servers fail to handle chunks with a negative size


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Vendor Statement


                          SGI Security Advisory

         Title:  Apache Web Server Chunk Handling vulnerability
       Number:  20020605-01-I
         Date:  July 12, 2002
    Reference:  SGI Security Advisory 20020605-01-A
    Reference:  CERT CA-2002-17
    Reference:  Apache Security Bulletin 20020617
    Reference:  CAN-2002-0392

- -----------------------
- --- Issue Specifics ---
- -----------------------

This bulletin is an update to SGI Security Advisory 20020605-01-A.

It has been reported that versions of the Apache web server up to and
including 1.3.24 and 2.0 up to and including 2.0.36 contain a bug in the
routines which deal with invalid requests which are encoded using chunked
encoding.  This bug can be triggered remotely by sending a carefully crafted
invalid request. This functionality is enabled by default.

See for
additional details.

SGI has investigated the issues and recommends the following steps for
neutralizing the exposure.  It is HIGHLY RECOMMENDED that these measures be
implemented on ALL vulnerable SGI systems.

These issues have been corrected in IRIX 6.5.17, where we are now supplying
a fixed version of Apache.  We are also making the fixed version of Apache
available on our security FTP site for prior releases of IRIX.

- --------------
- --- Impact ---
- --------------

The Apache webserver is supplied with IRIX versions since 6.5.12m/f as a
replacement for the older SGI FastTrack server.  It is installed by default,
and is enabled through "chkconfig" by default.

In order to determine if the Apache webserver is installed, execute the
following command:

  # versions -b | grep apache

If the following line is returned you are OK:

I  sgi_apache           07/10/2002  SGI Web Server based on Apache, 1.3.26

But if either of these are returned you are vulnerable:

I  sgi_apache           03/20/2001  SGI Apache Server, 1.3.17
I  sgi_apache           06/10/2001  SGI Apache Server, 1.3.20
I  sgi_apache           12/06/2001  SGI Web Server based on Apache, 1.3.22

These vulnerabilities might lead to a root compromise in some
configurations, and no local account is required.

These vulnerabilities have been publicly discussed in Usenet newsgroups
and mailing lists.

This vulnerability was assigned the following CVE:

- ----------------------------
- --- Temporary Workaround ---
- ----------------------------

SGI acknowledges that it may not always be possible to immediately install
patches or upgrade the operating system.  In those cases, we recommend
removing the Apache webserver and associated products by using the following

  # versions remove sgi_apache\*
 # versions remove websetup\*
 # versions remove gateway\*

It is not necessary to reboot the system after doing this.  You should
upgrade the operating system as soon as it is possible to do so.

- ----------------
- --- Solution ---
- ----------------

SGI has not provided a patch for these issues, but instead has rolled the
fixed Apache distribution into IRIX 6.5.17 and later releases of the
operating system.

   OS Version     Vulnerable?     Patch #      Other Actions
  ----------     -----------     -------      -------------
  IRIX 3.x          no                        Note 1
  IRIX 4.x          no                        Note 1
  IRIX 5.x          no                        Note 1
  IRIX 6.0.x        no                        Note 1
  IRIX 6.1          no                        Note 1
  IRIX 6.2          no                        Note 1
  IRIX 6.3          no                        Note 1
  IRIX 6.4          no                        Note 1
  IRIX 6.5          no                        Note 2
  IRIX 6.5.1        no                        Note 2
  IRIX 6.5.2        no                        Note 2
  IRIX 6.5.3        no                        Note 2
  IRIX 6.5.4        no                        Note 2
  IRIX 6.5.5        no                        Note 2
  IRIX 6.5.6        no                        Note 2
  IRIX 6.5.7        no                        Note 2
  IRIX 6.5.8        no                        Note 2
  IRIX 6.5.9        no                        Note 2
  IRIX 6.5.10       no                        Note 2
  IRIX 6.5.11       no                        Note 2
  IRIX 6.5.12       yes                       Note 2
  IRIX 6.5.13       yes   sgi_apache 1.3.26   Note 2 & 3
  IRIX 6.5.14       yes   sgi_apache 1.3.26   Note 2 & 3
  IRIX 6.5.15       yes   sgi_apache 1.3.26   Note 2 & 3
  IRIX 6.5.16       yes   sgi_apache 1.3.26   Note 2 & 3
  IRIX 6.5.17       no


     1) This version of the IRIX operating has been retired. Upgrade to an
       actively supported IRIX operating system.  See for more

     2) If you have not received an IRIX 6.5.X CD for IRIX 6.5, contact your
       SGI Support Provider or URL:

     3) Install sgi_apache 1.3.26 which is supplied with the IRIX 6.5.17
       Applications CD or available as sgi_apache-1.3.26.tar from:{6.5.13-6.5.16}

                ##### Patch File Checksums ####

The actual patch will be a tar file containing the following files:

Filename:                 sgi_apache
Algorithm #1 (sum -r):    24080 5 sgi_apache
Algorithm #2 (sum):       37968 5 sgi_apache
MD5 checksum:             1EE81B8F7A8DF9ED4D9AF507EA1D2755

Filename:                 sgi_apache.books
Algorithm #1 (sum -r):    65292 3274 sgi_apache.books
Algorithm #2 (sum):       32822 3274 sgi_apache.books
MD5 checksum:             CD6296A58A1B6F1FF2D6B212058D1C4D

Filename:                 sgi_apache.idb
Algorithm #1 (sum -r):    13477 281 sgi_apache.idb
Algorithm #2 (sum):       4276 281 sgi_apache.idb
MD5 checksum:             3144B64008FF66BF858434208C6BCB5B

Algorithm #1 (sum -r):    29483 97
Algorithm #2 (sum):       35420 97
MD5 checksum:             A7864555852DB7ACC913F049BFC46121

Filename:                 sgi_apache.src
Algorithm #1 (sum -r):    43010 6244 sgi_apache.src
Algorithm #2 (sum):       58317 6244 sgi_apache.src
MD5 checksum:             7D2A6A9A226327D8D9990F80635AED80

Filename:                 sgi_apache.sw
Algorithm #1 (sum -r):    20406 1852 sgi_apache.sw
Algorithm #2 (sum):       32509 1852 sgi_apache.sw
MD5 checksum:             371625EE5B321A76137AD1A18B23B4C0

- -------------------
- --- Information ---
- -------------------

SGI Security Advisories can be found at: and

SGI Security Patches can be found at: and

SGI patches for IRIX can be found at the following patch servers: and

SGI freeware updates for IRIX can be found at:

SGI fixes for SGI open sourced code can be found on:

SGI patches and RPMs for Linux can be found at: or

SGI patches for Windows NT or 2000 can be found at:

IRIX 5.2-6.4 Recommended/Required Patch Sets can be found at: and

IRIX 6.5 Maintenance Release Streams can be found at:

IRIX 6.5 Software Update CDs can be obtained from:

The primary SGI anonymous FTP site for security advisories and patches is (  Security advisories and patches are
located under the URL

For security and patch management reasons, (mirrors security FTP repository) lags behind and does not do a
real-time update.

- ------------------------
- --- Acknowledgments ----
- ------------------------

SGI wishes to thank Mark Litchfield, CERT, ISS and the users of the Internet
Community at large for their assistance in this matter.

- -----------------------------------------
- --- SGI Security Information/Contacts ---
- -----------------------------------------

If there are questions about this document, email can be sent to


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community.  This information is freely available to any person needing the
information and is available via anonymous FTP and the Web.

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located under the URL

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     includes its valid PGP signature.

Version: 2.6.2


Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Vendor References



An SGI Advisory describing this issue is available at: