BKDR_TDSS.SM


 ALIASES:

Trojan:Win32/Alureon.CT, TrojanDownloader:Win32/Renos, TrojanDownloader:Win32/Harnig.gen!P, TrojanDo (Microsoft); [2.nsis\3.nsis]:TDSS, [2.nsis\4.nsis]:Downloader-BWS, [2.nsis\5.nsis]:Generic Dropper.lr, [3.nsis]:G (McAfee); Downloader (Symantec); ARC:NSIS, ARC:[$PLUGINSDIR\Autorun.exe]:NSIS, [$PLUGINSDIR\Autorun.exe/$PLUGINSDIR\Games.exe]:Packed (Kaspersky); Trojan.Win32.Alureon.bk (v), Trojan.Win32.FraudPack.gen (v), Trojan.Win32.Bredolab.Gen.2 (v), Trojan (Sunbelt); Gen:Heur.Krypt.25 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

665,421 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

07 May 2012

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor creates the following folders:

  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Temp%\nsx3.tmp
  • %User Temp%\nsp6.tmp

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other System Modifications

This backdoor modifies the following file(s):

  • %Windows%\setuplog.txt

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It deletes the following files:

  • %User Temp%\nsx1.tmp
  • %User Temp%\nsx3.tmp
  • %User Temp%\nse4.tmp
  • %User Temp%\nsp6.tmp
  • %System%\spool\PRTPROCS\W32X86\7.tmp

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

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent\CurrentVersion\Parameters
TrapPollTimeMilliSecs = "3a98"

(Note: The default value data of the said registry entry is 3a98.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
Name = "e4u.exe"

(Note: The default value data of the said registry entry is iexplore.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
ID = "4b15a35e"

(Note: The default value data of the said registry entry is 41107b81.)

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\nsx2.tmp
  • %User Temp%\nsx3.tmp\Autorun.exe
  • %User Temp%\nsx3.tmp\BPFull.exe
  • %User Temp%\nsu5.tmp
  • %User Temp%\nsp6.tmp\Autorun.exe
  • %User Temp%\nsp6.tmp\Games.exe
  • %User Temp%\nsp6.tmp\EP.exe
  • %User Temp%\nsp6.tmp\e4u.exe
  • %System%\spool\PRTPROCS\W32X86\7.tmp

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

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}er.com/tdfpmmn/hohhveswgc.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/wcyijjt.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/jqqankx.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/hnkppz.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/ohnbbyyif.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/zgzzjjwli.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/irxhiiffp.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/zfpcdmakt.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/iouvvfgcd.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/bhrnbylv.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/mbhrobl.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/wtqanbo.php?adv=adv468
  • http://{BLOCKED}er.com/tdfpmmn/bhanx.php?{random characters}

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RFC1156Agent\CurrentVersion\Parameters
    • From: TrapPollTimeMilliSecs = "3a98"
      To: TrapPollTimeMilliSecs = ""3a98""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: Name = "e4u.exe"
      To: Name = ""iexplore.exe""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: ID = "4b15a35e"
      To: ID = ""41107b81""

Step 3

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\nsx2.tmp
  • %User Temp%\nsx3.tmp\Autorun.exe
  • %User Temp%\nsx3.tmp\BPFull.exe
  • %User Temp%\nsu5.tmp
  • %User Temp%\nsp6.tmp\Autorun.exe
  • %User Temp%\nsp6.tmp\Games.exe
  • %User Temp%\nsp6.tmp\EP.exe
  • %User Temp%\nsp6.tmp\e4u.exe
  • %System%\spool\PRTPROCS\W32X86\7.tmp

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Temp%\nsx3.tmp
  • %User Temp%\nsp6.tmp

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_TDSS.SM. 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.

Step 6

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %Windows%\setuplog.txt

Step 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Temp%\nsx1.tmp
  • %User Temp%\nsx3.tmp
  • %User Temp%\nse4.tmp
  • %User Temp%\nsp6.tmp
  • %System%\spool\PRTPROCS\W32X86\7.tmp


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