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TROJ_DLUCA.AB

June 18, 2013
 ALIASES:

TrojanDownloader:Win32/Dluca (Microsoft); Generic Downloader.be (McAfee); Adware.SafeSearch, Dialer.Adultchat (Symantec); Trojan-Downloader.Win32.Dluca.ci (Kaspersky); Trojan-Downloader.Dluca (v) (Sunbelt); Trojan horse Downloader.Dluca.FL (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan 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:

50,688 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

11 Jun 2013

Arrival Details

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

  • %Program Files%\common files\system\ms1src.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This Trojan modifies the following file(s):

  • %User Profile%\Application Data\Microsoft

(Note: %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.)

It deletes the following files:

  • %User Temp%\qdelwbi.tmp
  • %System%\safesearch.exe
  • %Program Files%\primesoft\safesearch\safesearch.exe
  • %System%\_SafeSearch.dll
  • %System%\SafeSearch.dll
  • %Program Files%\common files\system\ms1src.exe:Zone.Identifier
  • \ms1src_update.exe

(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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It deletes the following folders:

  • %Program Files%\primesoft\safesearch
  • %Program Files%\primesoft

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{00000000-0000-0000-0000-000000000001}\
InprocServer32

HKEY_CURRENT_USER\Software\Program Data

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch

HKEY_CURRENT_USER\Software\Program Info

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Program Data
SSET = "ECR#171A02951E83"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
GetIDRetryCounter = "0"

HKEY_CURRENT_USER\Software\Program Info
ClientID = "{1e68f7d7-9c22-4493-bb05-c86eef654a71}"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
LastWNK = "51b397cc"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
FlashID = "1399037"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
DaytimeDocID = "-1"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
DaytimeDocTime = "0"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
GetInfoRetryCounter = "0"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
LastWNK = "51b39819"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
DaytimeDocID = "0"

HKEY_CURRENT_USER\Software\InfoSoft\
qsearch
DaytimeDocTime = "51b3981b"

It modifies the following registry entries:

HKEY_CURRENT_USER\SessionInformation
ProgramCount = "1"

(Note: The default value data of the said registry entry is 2.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\Currentversion\Uninstall\
SafeSearch

HKEY_CURRENT_USER\Software\Microsoft\
Windows\Currentversion\Uninstall\
SafeSearch

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-1645522239-1292428093-682003330-1003
  • %User Profile%\RSA\MachineKeys
  • %User Temp%\WK_6.tmp
  • %User Temp%\WK_10.tmp
  • %User Temp%\WK_1C.tmp

(Note: %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 Details

This Trojan connects to the following possibly malicious URL:

  • http://w.{BLOCKED}ejtudlk-dfjkeid.com/wk/getclientid.wnk?{random characters}
  • http://w.{BLOCKED}ejtudlk-dfjkeid.com/wk/getclientinfo.wnk?{random characters}

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Delete this registry key

[ 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_CLASSES_ROOT\CLSID\{00000000-0000-0000-0000-000000000001}
    • InprocServer32
  • In HKEY_CURRENT_USER\Software
    • Program Data
  • In HKEY_CURRENT_USER\Software\InfoSoft
    • qsearch
  • In HKEY_CURRENT_USER\Software
    • Program Info

Step 3

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_CURRENT_USER\Software\Program Data
    • SSET = "ECR#171A02951E83"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • GetIDRetryCounter = "0"
  • In HKEY_CURRENT_USER\Software\Program Info
    • ClientID = "{1e68f7d7-9c22-4493-bb05-c86eef654a71}"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • LastWNK = "51b397cc"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • FlashID = "1399037"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • DaytimeDocID = "-1"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • DaytimeDocTime = "0"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • GetInfoRetryCounter = "0"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • LastWNK = "51b39819"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • DaytimeDocID = "0"
  • In HKEY_CURRENT_USER\Software\InfoSoft\qsearch
    • DaytimeDocTime = "51b3981b"

Step 4

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_CURRENT_USER\SessionInformation
    • From: ProgramCount = "1"
      To: ProgramCount = ""2""

Step 5

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 Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-1645522239-1292428093-682003330-1003
  • %User Profile%\RSA\MachineKeys
  • %User Temp%\WK_6.tmp
  • %User Temp%\WK_10.tmp
  • %User Temp%\WK_1C.tmp

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLUCA.AB. 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 7

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.

    • %User Profile%\Application Data\Microsoft

Step 8

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%\qdelwbi.tmp
  • %System%\safesearch.exe
  • %Program Files%\primesoft\safesearch\safesearch.exe
  • %System%\_SafeSearch.dll
  • %System%\SafeSearch.dll
  • %Program Files%\common files\system\ms1src.exe:Zone.Identifier
  • \ms1src_update.exe

Step 9

Restore these deleted registry keys/values from backup

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

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Currentversion\Uninstall
    • SafeSearch
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\Currentversion\Uninstall
    • SafeSearch


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