TROJ_DLUCA.AI

June 06, 2013
 ALIASES:

TrojanDownloader:Win32/Dluca.AI (Microsoft); Generic Downloader.p (McAfee); Downloader.Dluca (Symantec); Porn-Dialer.Win32.DialerComp (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Downloader.Dluca.AM (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:

32,768 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 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:

  • %System%\sp2ctr.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
sp2ctr = "%System%\sp2ctr.exe /nocomm"

Other System Modifications

This Trojan deletes the following files:

  • %User Temp%\delwbi.tmp
  • %System%\sp2ctr.exe:Zone.Identifier

(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 adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates\
F7EE4E3689C2DCF4A531C20954D158C1936D9A3C

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates\
1567DAAB1377FE3552D2F6F2A2FA80200135EDA5

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates\
F705E9D8DAA72DF53D068BF60B551EA3103D51D7

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates\
F7EE4E3689C2DCF4A531C20954D158C1936D9A3C
Blob = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates\
1567DAAB1377FE3552D2F6F2A2FA80200135EDA5
Blob = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates\
F705E9D8DAA72DF53D068BF60B551EA3103D51D7
Blob = "{random values}"

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

Restart in Safe Mode

[ Learn More ]

Step 3

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_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher\Certificates
    • F7EE4E3689C2DCF4A531C20954D158C1936D9A3C
  • In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher\Certificates
    • 1567DAAB1377FE3552D2F6F2A2FA80200135EDA5
  • In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher\Certificates
    • F705E9D8DAA72DF53D068BF60B551EA3103D51D7

Step 4

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\Windows\CurrentVersion\Run
    • sp2ctr = "%System%\sp2ctr.exe /nocomm"
  • In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher\Certificates\F7EE4E3689C2DCF4A531C20954D158C1936D9A3C
    • Blob = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher\Certificates\1567DAAB1377FE3552D2F6F2A2FA80200135EDA5
    • Blob = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\TrustedPublisher\Certificates\F705E9D8DAA72DF53D068BF60B551EA3103D51D7
    • Blob = "{random values}"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLUCA.AI. 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 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%\delwbi.tmp
  • %System%\sp2ctr.exe:Zone.Identifier


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