November 4, 2005

Linux Advisory Watch - November 4th 2005

Author: Benjamin D. Thomas

This week, advisories were released for lynx, OpenSSL, gnump3d, netpbmfree, gallery, phpmyadmin, SELinux PAM Local, TikiWiki, mantis, Ethereal, XLI, libgda, ImageMagick, kernel, and wget. The distributors include Debian, Gentoo, and Red Hat.

Hacks From Pax: SELinux And Access Decisions
Pax Dickinson

Security Contexts

SELinux makes access decisions by checking the security context of the subject (a process, sometimes associated with a user) against the action attempted (e.g. a file read) and the security context of the targeted object (such as a file or network port).

These contexts are divided into three parts: a user identity, a role, and a domain or type. In the current SELinux policy, access is not restricted based on user identities, so we'll focus on roles and domains in this article.

User Roles

On an SELinux system, unlike a standard Linux system, root has no special privileges inherent to the account. SELinux privileges are denoted by a user's role. A standard user is assigned a role of user_r, which gives no special privileges. System administrator accounts are assigned a role of staff_r, which permits what is known as a "role transition" to the sysadm_r role. The sysadm_r role is the equivalent of the root account on a non-SELinux system, it has unfettered access to the system.

A staff user transitions to the sysadm_r role by using the newrole command, as shown below.

newrole -r sysadm_r

The user is then prompted for his or her password, successful entry of which will result in transition to the new role. You can view your current role by issuing an id -Z command.

Domains and Types

Domains and types are synonyms, typically the term "domain" is used when referring to processes and the term "type" is used referring to files. Types are the primary method used by SELinux to make authorization decisions. The strict policy defines relatively few users and roles, but contains hundreds of types.

Types are assigned by the security policy based on the path of the file in question, and the policy also transitions processes into an appropriate domain based on the context of the executed file and the domain of the process executing the file.

For example, the Apache webserver executable file has a type of httpd_exec_t. When that file is executed by the init process at bootup, the policy forces the new process to transition into the httpd_t domain. The httpd_t domain has the ability to read web content denoted by the httpd_content_t type, but not to change it or access any other domains not required for proper webserver operation.

You can view the type of a given file by using the -Z option of ls, and you can view the domain a process is running in by using the -Z option of ps. These -Z options are specific to SELinux and will not function on a non-SELinux system.

Read Entire Article:
http://www.linuxsecurity.com/content/view/120622/49/


   Debian
  Debian: New lynx packages fix arbitrary
code execution
  27th, October, 2005
Updated package.
 
  Debian: New OpenSSL packages fix cryptographic
weakness
  27th, October, 2005
Updated package.
 
  Debian: New lynx-ssl packages fix arbitrary
code execution
  27th, October, 2005
Updated package.
 
  Debian: New gnump3d packages fix several
vulnerabilities
  28th, October, 2005
Updated package.
 
  Debian: New netpbm-free packages fix
arbitrary code execution
  28th, October, 2005
Updated package.
 
  Debian: New gallery packages fix privilege
escalation
  2nd, November, 2005
Updated profile.
 
  Debian: New phpmyadmin packages fix several
vulnerabilities
  2nd, November, 2005
Updated profile.
 
   Gentoo
  Gentoo: SELinux PAM Local password guessing
attack
  28th, October, 2005
A vulnerability in the SELinux version of PAM allows a local
attacker to brute-force system passwords.
 
  Gentoo: TikiWiki XSS vulnerability
  28th, October, 2005
TikiWiki is vulnerable to cross-site scripting attacks.
 
  Gentoo: Mantis Multiple vulnerabilities
  28th, October, 2005
Mantis is affected by multiple vulnerabilities ranging from
information disclosure to arbitrary script execution.
 
  Gentoo: Ethereal Multiple vulnerabilities
in protocol dissectors
  30th, October, 2005
Ethereal is vulnerable to numerous vulnerabilities, potentially
resulting in the execution of arbitrary code or abnormal termination.
 
  Gentoo: XLI, Xloadimage Buffer overflow
  30th, October, 2005
XLI and Xloadimage contain a vulnerability which could potentially
result in the execution of arbitrary code.
 
  Gentoo: libgda Format string vulnerabilities
  2nd, November, 2005
Two format string vulnerabilities in libgda may lead to the
execution of arbitrary code.
 
  Gentoo: QDBM, ImageMagick, GDAL RUNPATH
issues
  2nd, November, 2005
Multiple packages suffer from RUNPATH issues that may allow
users in the "portage" group to escalate privileges.
 
   Red
Hat
  RedHat: Important: kernel security update
  27th, October, 2005
Updated kernel packages that fix several security issues and
a page attribute mapping bug are now available for Red Hat Enterprise
Linux 4. This update has been rated as having important security impact
by the Red Hat Security Response Team.
 
  RedHat: Moderate: curl security update
  2nd, November, 2005
Updated curl packages that fix a security issue are now available.
This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

http://www.linuxsecurity.com/content/view/120707

 
  RedHat: Important: wget security update
  2nd, November, 2005
Updated wget packages that fix a security issue are now available.
This update has been rated as having important security impact by the
Red Hat Security Response Team.
 
  RedHat: Important: openssl security update
  2nd, November, 2005
Updated OpenSSL packages that fix a remote denial of service
vulnerability are now available for Red Hat Enterprise Linux 2.1 This
update has been rated as having important security impact by the Red Hat
Security Response Team.
 
  RedHat: Moderate: openssl096b security
update
  2nd, November, 2005
Updated OpenSSL096b compatibility packages that fix a remote
denial of service vulnerability are now available. This update has been
rated as having moderate security impact by the Red Hat Security Response
Team.
 

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