BKDR_ZLOB.SMGS

 Analysis by: Karl Dominguez

 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW


This backdoor may be downloaded by other malware/grayware from remote sites.

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

09 Aug 2010

Payload:

Terminates processes, Compromises system security, Downloads files

Arrival Details

This backdoor may be downloaded by the following malware/grayware from remote sites:

  • BKDR_TDSS.SIP

It may be downloaded from the following remote sites:

  • http://buntermah.com/dx.php

Installation

This backdoor drops the following copies of itself into the affected system:

  • %Application Data%\{random characters}.exe
  • %System%\ernel32.dll
  • %System%\spool\prtprocs\w32x86\{random}.dll

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It injects codes into the following process(es):

  • spoolsv.exe
  • svchost.exe

Autostart Technique

The scheduled task executes the malware every:

  • At User Login

Other System Modifications

This backdoor adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UacDisableNotify = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\spoolsv.exe = %System%\spoolsv.exe:*:Enabled:spoolsv.exe"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters
NameServer = {BLOCKED}.{BLOCKED}.164.128,93.188.160.208

(Note: The default value data of the said registry entry is {user defined}.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters
DhcpNameServer = {BLOCKED}.{BLOCKED}.164.128,93.188.160.208

(Note: The default value data of the said registry entry is {user defined}.)

Process Termination

This backdoor terminates the following processes if found running in the affected system's memory:

  • mbam.exe
  • spybotsd.exe
  • combofix.exe
  • superantispyware.exe
  • mrt.exe

Other Details

This backdoor does the following:

  • It uses Simple Object Access Protocol (SOAP) to find the network routers and get the following information:
    • Manufacturer
    • Model Name
    • Model Number
    • Control URL
  • It will then access the control URL of the router depending on the discovered UPnP device:
    • http://{control URL}/index.asp
    • http://{control URL}/dlink/hwiz.html
    • http://{control URL}/home.asp
    • http://{control URL}/wizard.htm
    • http://{control URL}/login.asp
    • http://{control URL}/cgi/b/users/switchpopup/
  • It uses brute force to access the routers using the following strings:
    • Usernames:

      • admin
      • {blank}
      • root
      • Admin
      • 1234
    • Passwords:
      • Password
      • pass
      • password
      • root
      • router
      • admin
      • administrator
      • {blank}
      • 0
      • 0P3N
      • 1234
      • 12345
      • 123456
      • a
      • a6a7wimax
      • adslnadam
      • adslroot
      • airlive
      • alice
      • atlantis
      • bewan
      • cableroot
      • cciadmin
      • conexant
      • ecom
      • epicrouter
      • friend
      • hamlet
      • hayesadsl
      • highspeed
      • hsparouter
      • motorola
      • mysweex
      • password1
      • sitecom46
      • sky
      • smcadmin
      • stccpe_2007
      • telekom
      • telus
      • telus177
      • tmadmin
      • trendchip
      • ttnet
      • utstar
      • vodafone
      • zoomadsl
  • The malware can also retreive stored user names and passwords in by using the CredEnumerateA function and GID abe2869f-9b47-4cd9-a358-c22904dba7f7. If successful, the malware will add an open port and retreive the External IP address of the router. The information will be sent to the following site, making the network is vulnerable to remote attacks:
    • http://{BLOCKED}ntermah.com/dx.php
  • In addition to opening a port in the router, it also changes the DNS settings of the affected system to the following:
    • Preferred DNS Server: {BLOCKED}.{BLOCKED}.164.128
    • Alternate DNS Server: {BLOCKED}.{BLOCKED}.160.208

    As a result, connections from the affected system will pass through the attacker's system and enable the attacker to control and monitor communications.

  • It also monitors Internet browsers to observe search engines. Search results will be intercepted by the malware. After a timeout of 10 seconds, the malware will change the search results and redirect users to results5.google.com then to another random page. It monitors the following browsers:
    • iexplore.exe
    • firefox.exe
    • safari.exe
    • opera.exe

    It monitors the following search engines:

    • .google.
    • search.yahoo.
    • search.msn.
    • search.live.
    • altavista.com
    • ask.com
    • search.aol.
    • search.icq.
    • alltheweb.com
    • bing.com
    • yandex.ru
    • rambler.ru
    • go.mail.ru
    • sm.aport.ru

    It monitors the following URL strings:

    • .youtube.
    • .wikipedia.
    • .yahoo.
    • rds.yahoo.
    • overture.
    • .yimg.com
    • wikimedia.
    • amazon.com
    • hotmail.
    • .msn.com
    • .live.com
    • microsoft.
    • altavista.
    • atdmt.com
    • wzus1.ask.
    • opselect.com
    • aolcdn
    • aolsearch
    • .aol.
    • revsci.net
    • atwola.
    • digitalcity.
    • .icq.
    • o.aolcdn.com
    • alltheweb.
    • bing.
    • .yandex.
    • tns-counter.
    • .rambler.
    • .rl0.ru
    • .begun.
    • list.ru
    • .mail.ru
    • z5x.net
    • imgsmail.ru
    • .aport.
    • yadro.ru
    • .ag.ru

  • It accesses the following URL to download an updated copy of itself or another malware:
    • http://{BLOCKED}ume.com/kx.php

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove the malware/grayware file dropped/downloaded by BKDR_ZLOB.SMGS

    BKDR_TDSS.SIP

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_ZLOB.SMGS

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UacDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • EnableLUA = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\spoolsv.exe = %System%\spoolsv.exe:*:Enabled:spoolsv.exe

Step 6

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    • From: NameServer = {BLOCKED}.{BLOCKED}.164.128,93.188.160.208
    • To: NameServer = {user defined}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    • From: DhcpNameServer = {BLOCKED}.{BLOCKED}.164.128,93.188.160.208
    • To: DhcpNameServer = {user defined}

Step 7

Search and delete the file detected as BKDR_ZLOB.SMGS

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 8

To delete the added job file:

  1. Click on Start>Programs>Accessories>System Tools>Scheduled Tasks
  2. Double-click on a job file.
  3. Check if the malware path and file name is in the Run: box.
  4. If it does, delete the job file.
  5. Repeat step 2-4 for the remaining job files.

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZLOB.SMGS. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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