[UNIX] Astaro Security Linux File Permissions Problem

From: support@securiteam.com
Date: 02/13/02


From: support@securiteam.com
To: list@securiteam.com
Date: Wed, 13 Feb 2002 16:36:31 +0100 (CET)

The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion

When was the last time you checked your server's security?
How about a monthly report?
http://www.AutomatedScanning.com - Know that you're safe.
- - - - - - - - -

  Astaro Security Linux File Permissions Problem
------------------------------------------------------------------------

SUMMARY

iDEFENSE Intelligence Operations discovered security issues in improper
file and directory permissions during an audit of
<http://www.astaro.com/> Astaro AG's Astaro Linux. Astaro Linux designates
a number of files and directories as world writeable that should probably
not be. This, combined with other more serious flaws, could potentially
result in system compromise or denial of service.

DETAILS

Analysis:
World writeable files and directories are dangerous because any user on
the system, even one running in a restricted account such as "nobody" can
access the files, write to them, and potentially delete them. World
writeable directories can be especially dangerous when they are used to
store files covertly. Any directories and files contained within the world
writeable directory can potentially be modified.

Several sensitive configuration files and directories are world writeable,
meaning an attacker with any level of access to the root file system could
cause damage or subvert the services/applications relying on those files.

The following files are world writeable:
 /etc/protocols
 /etc/ssh/ssh_host_dsa_key.pub
 /etc/ssh/ssh_host_key.pub

It is unknown whether the following files need to be world writeable for
the system to function properly, but it appears safe to remove the world
writeable attribute:

 /etc/up2date/latest_md5sum
 /wtc/wfe/conf/console
 /wtc/wfe/conf/nameserver
 /wtc/wfe/conf/netzkartendata
 /var/log/account/timestamp

Astaro Linux also contains a number of world writeable directories:
 /var
 /etc/up2date/lib1
 /etc/up2date/lib2

In general, the /var directory should not be world writeable on any *nix
system since by filling up the associated partition, an attacker may
prevent log files from being written to hide his activity.

Detection:
Finding world writeable files and directories is easy, simply use the
"find" command:
 find / -type d -perm +002
 find / -type f -perm +002

These commands will list all world writeable directories and files
respectively. Some of the directories, such as /tmp, are meant to be world
writeable, and leaving them as such is relatively safe.

Workaround:
Removing the world writeable bit on the files can be accomplished using
chmod:
 chmod o-w filename

This will work for both files and directories.

Vendor response:
 <mailto:mhennig@astaro.com> Markus Hennig of Astaro promptly confirmed
the incorrect file permissions and worked with us responsibly to resolve
these issues. The latest Up2Date 2.022 fixes the file permissions, which
is now currently available on Astaro Up2Date servers.

ADDITIONAL INFORMATION

The information has been provided by <mailto:dendler@idefense.com> David
Endler.

========================================

This bulletin is sent to members of the SecuriTeam mailing list.
To unsubscribe from the list, send mail with an empty subject line and body to: list-unsubscribe@securiteam.com
In order to subscribe to the mailing list, simply forward this email to: list-subscribe@securiteam.com

====================
====================

DISCLAIMER:
The information in this bulletin is provided "AS IS" without warranty of any kind.
In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.



Relevant Pages

  • RE: [Full-Disclosure] Top 15 Reasons Why Admins Use Security Scan ners
    ... printout of the file permissions of every file on every system. ... They insisted on a printout. ... Top 15 Reasons Why Admins Use Security ... Charter: http://lists.netsys.com/full-disclosure-charter.html ...
    (Full-Disclosure)
  • Re: Error convert applying security template
    ... and lock down security. ... I belive this template replaces the file permissions. ... Unable to establish connection with global catalog. ... >> security template as follows. ...
    (microsoft.public.win2000.security)
  • [fw-wiz] The New Security Threat: Lawyers?
    ... just thought I would toss this one into your capable hands for ... "A number of security experts seem to believe that lawsuits resulting from ... customers realize that their information was pilfered as well. ... software or hardware vendor for damages if that vendor's products are not ...
    (Firewall-Wizards)
  • Re: Access to external javascript file denied
    ... The file permissions on the DispatchRuleControl.js file are identical to the ... I'm wondering whether this is an ASP.NET security issue rather than an IIS ... the reason I suspected IIS first and foremost. ... "Dan" wrote: ...
    (microsoft.public.inetserver.iis.security)
  • Re: Microsoft Security Advisory Notification
    ... >> Al Jarvi (MS-MVP Windows Networking) ... >>> Security Advisories Updated or Released Today ... >>> International customers can get support from their local Microsoft ... >>> DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ...
    (microsoft.public.windowsxp.work_remotely)