RE: Microsoft RPC DCOM exploit descriptions

From: Troy Murray (murrayt5at_private)
Date: Tue Aug 12 2003 - 05:38:38 PDT

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    Internet Security Systems (http://www.iss.net) has released a scan tool to
    check for the MS03-026 patch on Windows servers.  I've downloaded and run
    this tool, command-line only, on my servers and it reports correctly that
    they are patched.  Running a scan on the 35-10.40.x range though yields 5
    systems that are not patched.  Not sure if there is a way to track down who
    they belong to or not to get them patched.
    
    You can grab the tool here:
    http://www.iss.net/support/product_utilities/ms03-026rpc.php
    
    -----------------------------------
    Troy D. Murray
    Michigan State University
    College of Human Medicine
    Department of Medicine
    Immunohematology and Serology Laboratory
    B228 Life Science Building
    East Lansing, MI 48824-1034
    (E) murrayt5at_private
    (P) 517.432.3545
    (F) 517.353.5436
    (W) http://msuhla.chm.msu.edu
    MSN: troymurrayat_private
    AIM: troymurray72 
    
    -----Original Message-----
    From: owner-msusecat_private [mailto:owner-msusecat_private] On Behalf
    Of Joe Budzyn
    Sent: Tuesday, August 05, 2003 8:56 AM
    To: msusecat_private
    Subject: Microsoft RPC DCOM exploit descriptions
    
    
    The following exploit descriptions are from the fine folks at Purdue
    University.  These computers were hacked using the Microsoft RPC DCOM
    vulnerability.
    
    I have seen at lest one machine on our campus that matches Variant #1 so
    far.  Please keep in mind that even if a computer does not match either
    variant below, it may still be hacked.
    
    As with any sort of post-hacking recovery, please use caution.  The
    instructions involve steps which may damage an installed operating system. I
    have not tried to recover a computer with these instructions and can make no
    guarantees.
    
    Joe Budzyn
    --
    Joe Budzyn
    Michigan State University - Incident Response Team
    Phone: (517) 355-4500 x162
    http://www.security.msu.edu
    abuseat_private
    
    
    
    Exploit Variants:
    ----------------------------------------------------------------------------
    ----
    Variant 1
    
    The following file is uploaded to vulnerable systems:
    
     %WINDIR%\system32\NX.EXE
    
    This file is a Paquet Builder self-executing (SFX) file.
    When executed on the compromised machine, the SFX creates the following file
    structure:
    
     %WINDIR%\system32\qossrv
         - - v1.0D (Haley) -
         - aysshell.exe
         - cdir.txt
         - csrss.exe
         - FireDeamon.exe
         - libeay32.dll
         - mswinsck.ocx
         - pskill.exe
         - secure.exe
         - ServUPerfCount.dll
         - setup.bat
         - ssleay32.dll
         - wget.exe
         - WinExplorer.dll
         - winmgnt.exe
    
    After uncompressing these files, the SFX file is instructed to launch the
    file %WINDIR%\system32\qossrv\SETUP.BAT to install additional files and
    services, as well as reconfigure DCOM.  Even though SETUP.BAT runs from the
    command line, it is not seen by the user.
    
    Using the UPX unpacker the content of these files is:
    
      winmgnt.exe -- Serv-U Mini-FTP server
      csrss.exe   -- pAdmin utility with H|TTP and DCC capabilities
      Secure.exe  -- Possibly a secure shell?  No good clues from strings
    output.  Appears to reference VBA libraries
    
    After SETUP.BAT executes, the following files can be found:
    
     %WINDIR%\system32
         - securedcom.reg
         - securedcom.reg.1
     %WINDIR%\system32\qossrv
         - aysinstlog.txt
         - securedcom.reg
         - secure.bat
         - go.bat
         - SystemUptimeLog.ocx
    
    In addition, three services are installed using aysshell.exe. This is a
    utility by Prism Microsystems called At Your Service that allows a user to
    easily run almost any executable file or script as a service.  Information
    on this product can be found at:
    
    (http://www.prismmicrosys.com/atyourservice/atyourservice-index.htm)
    
    This is used to launch csrss.exe, secure.exe, and winmgnt.exe as system
    services.  The services can be viewed in the Services Console in Windows
    2000 or Windows XP are as follows:
    
         "NTF"    (this is WINMGNT.EXE)
         "NTP"    (this is CSRSS.EXE)
         "NTS"    (this is SECURE.EXE)
    
    WINMGNT.EXE is the executable for ServU-FTP.  ServU-FTP is popular for this,
    as it is compact, and easily portable from machine to machine.  It listens
    on ports 5555 and 48522.  Checking for connections on these ports is also
    recommended.
    
    What calls GO.BAT or SECURE.BAT is undetermined, but both of these batch
    files simply import the securedcom.reg into the local registry.  This
    disables the DCOM service.
    
    After this is complete, the "Computer Browser" and "Server" services are no
    longer running.  They can be manually started, but do not run as expected on
    system boot up.
    
    How to clean machines infected with variant 1:
    
    Stop the Services:
         Net Stop "NTP"
         Net Stop "NTS"
         Net Stop "NTF"
    
    Unregister the OCX Files:
         regsvr32 /u /s %WINDIR%\system32\qossrv\mswinsck.ocx
         regsvr32 /u /s %WINDIR%\system32\qossrv\systemuptimelog.ocx
    
    Delete the Files:
         del %WINDIR%\system32\nx.exe
         del %WINDIR%\system32\securedcom.reg
         del %WINDIR%\system32\securedcom.reg.1
         del %WINDIR%\system32\qossrv\*.*
    
    Remove the Directory:
         rd /s /q %WINDIR%\system32\qossrv
    
    Delete the Registry Value:
         HKLM\Software\Microsoft\Windows\CurrentVersion\Run\NTLDM
    
    Delete the Registry Keys:
         HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_NTF
         HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_NTP
         HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_NTS
         HKLM\SYSTEM\CurrentControlSet\Services\NTF
         HKLM\SYSTEM\CurrentControlSet\Services\NTP
         HKLM\SYSTEM\CurrentControlSet\Services\NTS
    
            Note :  Some registry entries may be installed with special
    permissions so that only the SYSTEM has full control. To remove them, right
    click on the entry, click permissions, and give everyone full control.  You
    will then be able to delete them.
    
    Modify the following Registry Key:
         HKLM\Software\Microsoft\Ole\EnableDCOM=Y
    
    Restart the Services:
         NET START "Server"
         NET START "Computer Browser"
    
    ----------------------------------------------------------------------------
    ----
    
    Variant 2
    
    The services created by variant 2 are TCPIPenum, NTLMsDB, and IPconfig
    
    Payload is installed in WINNT regardless of your actual Windows folder.
    Administrators may wish to hand clean these folders as they may contain
    essential items.  Also Note that the folders themselves have both the hidden
    and system attributes. You may need deltree which is included in the cleanup
    package in case you don't already have it.
    
    The following files must be deleted:
    
    C:\WINNT\system32\config\aysshell.exe
    C:\WINNT\system32\dhcp\csrsslsrms.dll
    C:\WINNT\system32\dhcp\explorer.exe
    C:\WINNT\system32\dhcp\fport.exe C:\WINNT\system32\dhcp\igfxtray.exe
    C:\WINNT\system32\dhcp\nc.exe C:\WINNT\system32\dhcp\ntlmconf.dll
    C:\WINNT\system32\dhcp\pskill.exe C:\WINNT\system32\dhcp\pslist.exe
    C:\WINNT\system32\dhcp\rar.exe C:\WINNT\system32\dhcp\reg.exe
    C:\WINNT\system32\dhcp\rmns.exe C:\WINNT\system32\dhcp\service.exe
    C:\WINNT\system32\dhcp\SystemUptimeLog.ocx
    C:\WINNT\system32\dhcp\tlister.exe
    C:\WINNT\system32\dhcp\wget.exe C:\WINNT\system32\dhcp\winexplorer.dll
    C:\WINNT\system32\dhcp\home\tar.exe
    C:\WINNT\system32\restore\binary.gif
    C:\WINNT\system32\restore\compressed.gif
    C:\WINNT\system32\restore\csrss.exe
    C:\WINNT\system32\restore\del.gif C:\WINNT\system32\restore\dir.gif
    C:\WINNT\system32\restore\folder.open.gif
    C:\WINNT\system32\restore\image1.gif
    C:\WINNT\system32\restore\image2.gif
    C:\WINNT\system32\restore\movie.gif
    C:\WINNT\system32\restore\MSWINSCK.OCX
    C:\WINNT\system32\restore\pdf.gif C:\WINNT\system32\restore\pskill.exe
    C:\WINNT\system32\restore\reg.exe C:\WINNT\system32\restore\script.gif
    C:\WINNT\system32\restore\service.exe
    C:\WINNT\system32\restore\sound2.gif
    C:\WINNT\system32\restore\tar.gif C:\WINNT\system32\restore\text.gif
    C:\WINNT\system32\restore\unknown.gif
    %windir%\system32\securedcom.reg
    %windir%\system32\wge.exe
    
    The following registry entry must be removed:
    
    Registry Value:
    
    HKEY_LOCAL_MACHINE\software\microsoft\windows\current_version\run\QoSs
    rv
    $ (runs %windir%\system32\restore\csrss.exe)
    
    Registry Keys:
    
    HKEY_LOCAL_MACHINE\system\CurrentControlSet\Enum\root\legacy_tcpipenum
    HKEY_LOCAL_MACHINE\system\CurrentControlSet\Enum\root\legacy_ntlmsdb
    HKEY_LOCAL_MACHINE\system\CurrentControlSet\services\ipconfig
    HKEY_LOCAL_MACHINE\system\CurrentControlSet\services\TCPIPenum
    HKEY_LOCAL_MACHINE\system\CurrentControlSet\services\NTLMsDB
    



    This archive was generated by hypermail 2b30 : Tue Aug 12 2003 - 10:57:48 PDT