The OpenNET Project
 
Search (keywords):  SOFT ARTICLES TIPS & TRICKS SECURITY
LINKS NEWS MAN DOCUMENTATION


[ESA-20011019-02] kernel: Local DoS and root compromise


<< Previous INDEX Search src Set bookmark Go to bookmark Next >>
Date: Fri, 19 Oct 2001 12:16:32 -0400 (EDT)
From: EnGarde Secure Linux <[email protected]>
To: [email protected], [email protected]
Subject: [ESA-20011019-02]  kernel: Local DoS and root compromise

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


+------------------------------------------------------------------------+
| EnGarde Secure Linux Security Advisory                October 19, 2001 |
| http://www.engardelinux.org/                           ESA-20011019-02 |
|                                                                        |
| Package:  kernel                                                       |
| Summary:  Local DoS and root compromise                                |
+------------------------------------------------------------------------+

  EnGarde Secure Linux is a secure distribution of Linux that features
  improved access control, host and network intrusion detection, Web
  based secure remote management, complete e-commerce using AllCommerce,
  and integrated open source security tools.


OVERVIEW
- --------
  There are two vulnerabilities in the kernel which can allow a local
  attacker to either obtain root privileges or lock the machine up for
  an arbitrary amount of time.


DETAIL
- ------
  There are two vulnerabilities in the version of the kernel which
  shipped with EnGarde v1.0.1:

    1) There is another local root exploit using the kernel's ptrace
       capabilities.

    2) The kernel can be forced to remain in path_walk() while
       traversing a very deep tree of symbolic links for an arbitrary
       amount of time, resulting in a local DoS attack.

  Both vulnerabilities were discovered by Nergal ([email protected]).

  A note from Nergal's advisory:

    "In order for this flaw to be exploitable, /usr/bin/newgrp must be
     setuid root and world-executable. Additionally, newgrp, when run
     with no arguments, should not prompt for password. This conditions
     are satisfied in case of most popular Linux distributions (but not
     Openwall GNU/*/Linux)."

  Please note that EnGarde Secure Linux does not ship with the 'newgrp'
  utility, nor does it ship with any other setuid/setgid executables
  which can be used to exploit this bug.  Thus, EnGarde Secure Linux is
  not vulnerable to the ptrace flaw (item #1 above).

  Both vulnerabilies are very serious and all users are recommended to
  upgrade immediately using the special SOLUTION in this advisory.


SOLUTION
- --------
  All users should upgrade to the most recent version, as outlined in
  this advisory.

  Please note that kernel upgrades are not available through Guardian
  Digital Secure Update.  Please follow the steps outlined below to
  upgrade your system manually.  Updates can be obtained from:

    ftp://ftp.engardelinux.org/pub/engarde/stable/updates/
    http://ftp.engardelinux.org/pub/engarde/stable/updates/

  Please read and understand this entire section before you attempt to
  upgrade the kernel.

  Initial Steps
  -------------
    1) Verify the machine is either:

       a) booted into a "standard" kernel; or
       b) LIDS is disabled (/sbin/lidsadm -S -- -LIDS_GLOBAL)

    2) Determine which kernels you currently have installed:

         # rpm -qa --qf "%{NAME}\n" | grep kernel

    3) Download the new kernels that match what you have installed
       (based on step 2) from the "UPDATED PACKAGES" section of this
       advisory.


  Installation Steps
  ------------------
    4) Install the new packages.  The packages will automagically
       update /etc/lilo.conf by commenting out any old EnGarde images
       and replacing them with the new ones:

         # rpm -i <kernel 1> <kernel 2> ...

    5) Re-run LILO.  If you see any errors then open /etc/lilo.conf in
       your favorite text editor and make the appropriate changes:

         #  /sbin/lilo

  
  Final Steps
  -----------
    6) If you did not see any LILO errors then your new kernel is now
       installed and your machine is ready to be rebooted:

         # reboot


UPDATED PACKAGES
- ----------------
  These updated packages are for EnGarde Secure Linux 1.0.1 (Finestra).

  Source Packages:

    SRPMS/kernel-2.2.19-1.0.20.src.rpm
      MD5 Sum:  6a58f06ed68b1d7d967f523712ee8835

  Binary Packages:

    i386/kernel-2.2.19-1.0.20.i386.rpm
      MD5 Sum:  3704b6ced3c76c02c52238768cdeb1f3

    i386/kernel-lids-mods-2.2.19-1.0.20.i386.rpm
      MD5 Sum:  f4140c01e414e52204a4bab8ac600fa7

    i386/kernel-smp-lids-mods-2.2.19-1.0.20.i386.rpm
      MD5 Sum:  d02eb3e039cc37f15c7e6e56ece2d35a

    i386/kernel-smp-mods-2.2.19-1.0.20.i386.rpm
      MD5 Sum:  dd89db42a52786e3aeaf17deab647df4


    i686/kernel-2.2.19-1.0.20.i686.rpm
      MD5 Sum:  0854c91dd5d178e44655d836da5d2fd3

    i686/kernel-lids-mods-2.2.19-1.0.20.i686.rpm
      MD5 Sum:  98823cfce2f4e4d8c7f10372e7fc6971

    i686/kernel-smp-lids-mods-2.2.19-1.0.20.i686.rpm
      MD5 Sum:  502b174927b2361eebd58e93422cbb25

    i686/kernel-smp-mods-2.2.19-1.0.20.i686.rpm
      MD5 Sum:  e38e6b160c5d91fb64b02744b845b0b2


REFERENCES
- ----------

  Guardian Digital's public key:
    http://ftp.engardelinux.org/pub/engarde/ENGARDE-GPG-KEY

  Credit for the discovery of this bug goes to:
    Rafal Wojtczuk <[email protected]>

  Official Web Site of the Linux Kernel:
    http://www.kernel.org/

  Security Contact:    [email protected]
  EnGarde Advisories:  http://www.engardelinux.org/advisories.html

- --------------------------------------------------------------------------
$Id: ESA-20011019-02-kernel,v 1.3 2001/10/18 20:26:35 rwm Exp $
- --------------------------------------------------------------------------
Author: Ryan W. Maple, <[email protected]> 
Copyright 2001, Guardian Digital, Inc.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.4 (GNU/Linux)
Comment: For info see http://www.gnupg.org

iD8DBQE70FHoHD5cqd57fu0RAsUFAKCRfsVCyQClt/+icF5mSK3lztpSeACfZyRv
z9MnxfOxqI/Wqcg3gtD4rJ0=
=ob5F
-----END PGP SIGNATURE-----

<< Previous INDEX Search src Set bookmark Go to bookmark Next >>



Партнёры:
PostgresPro
Inferno Solutions
Hosting by Hoster.ru
Хостинг:

Закладки на сайте
Проследить за страницей
Created 1996-2024 by Maxim Chirkov
Добавить, Поддержать, Вебмастеру