TS-2007-002-0: BlueCat Networks Adonis root Privilege Access

Template Security Security Advisory

BlueCat Networks Adonis root Privilege Access

Date: 2007-08-06
Advisory ID: TS-2007-002-0
Vendor: BlueCat Networks, http://www.bluecatnetworks.com/
Revision: 0

Contents

Summary
Software Version
Details
Impact
Exploit
Workarounds
Obtaining Patched Software
Credits
Revision History

Summary

Template Security has discovered a serious user input
validation vulnerability in the BlueCat Networks Proteus IPAM
appliance. Proteus can be used to upload files to managed
Adonis appliances to be downloadable by TFTP from the
appliance. A Proteus administrator with privilege to add TFTP
files and perform TFTP deployments can overwrite existing files
and create new files as root on the Adonis DNS/DHCP appliance.
This can be used for example to overwrite the system password
database and change the root account password.

Software Version

Proteus version 2.0.2.0 and Adonis version 5.0.2.8 were tested.

Details

Proteus allows TFTP files to be named by an administrator, and
there is no data validation performed for user input such as
relative paths. Files are supposed to be copied only to the
/tftpboot/ directory, and the file copy is performed with root
privilege. This means for example that a file named
"…/etc/shadow" will overwrite the shadow password database
"/etc/shadow".

Impact

Successful exploitation of the vulnerability will result in
root access on the Adonis appliance.

Exploit

0) Create a new TFTP Group in a Proteus configuration.

1) Add a TFTP deployment role specifying an Adonis appliance to
the group.

2) At the top-level folder in the new TFTP group, add a file
named "…/etc/shadow" (without the quotes) and load a file
containing the following line:

 root:Im0Zgl8tnEq9Y:13637:0:99999:7:::

 NOTE: The sshd configuration uses the default setting
 'PermitEmptyPasswords no', so we specify a password of
 bluecat.

3) Deploy the configuration to the Adonis appliance.

4) You can now login to the Adonis appliance as root with
password bluecat.

 $ ssh [email protected]
 [email protected]'s password: 
 # cat /etc/shadow
 root:Im0Zgl8tnEq9Y:13637:0:99999:7:::

 NOTE: This example assumes SSH is enabled, iptables permits
 port tcp/22, etc.

Many attack variations are possible, such as changing system
startup scripts to modify the iptables configuration on the
appliance.

Workarounds

The attack can be prevented by creating an access right
override at the configuration level to disable TFTP access for
each administrator.

Obtaining Patched Software

Contact the vendor.

Credits

defaultroute discovered this vulnerability while performing a
security review of the Proteus IPAM appliance (a discovery
fueled by Red Bull and techno). defaultroute is a member of
Template Security.

Revision History

2007-08-06: Revision 0 released