ALIASES:

Trojan:Win32/Neurevt.A (Microsoft); RDN/Generic Dropper!hk (McAfee); Trojan.Gen.2 (Symantec); Trojan-Dropper.Win32.Injector.hycj (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Dropper.Generic8.CNH (AVG)

 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: 421,888 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 08 Apr 2014

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 drops the following copies of itself into the affected system:

  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}\uwozkyfqm.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).)

It creates the following folders:

  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}

(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 backdoor 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:

  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}\uwozkyfqm.exe:Zone.Identifier

(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_CURRENT_USER\Software\Win7zip

HKEY_CURRENT_USER\Software\Classes\
CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392\
CG1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
uwozkyfqm.exe

HKEY_LOCAL_MACHINE\Software\Win7zip

HKEY_CURRENT_USER\Software\Classes\
CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392\
CS1

HKEY_CURRENT_USER\Software\Classes\
CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392\
CW1

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Win7zip
Uuid = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Win7zip
Uuid = "{random values}"

It deletes the following registry keys:

HKEY_CURRENT_USER\CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\
11440392\CW1

Dropping Routine

This backdoor drops the following files:

  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}\0000db9a.txt
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-1645522239-1292428093-682003330-1003

(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).. %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.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}o.ru/forums/order.php

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_CURRENT_USER\Software
    • Win7zip
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392
    • CG1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • uwozkyfqm.exe
  • In HKEY_LOCAL_MACHINE\Software
    • Win7zip
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392
    • CS1
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392
    • CW1

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\Win7zip
    • Uuid = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Win7zip
    • Uuid = "{random values}"

Step 4

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.
  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}\0000db9a.txt
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-1645522239-1292428093-682003330-1003

Step 5

Search and delete this folder

[ 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.
  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_NEUREVT.AC. 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.

  • %Program Files%\Common Files\Identities.{2227A280-3AEA-1069-A2DE-08002B30309D}\uwozkyfqm.exe:Zone.Identifier

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_CURRENT_USER\CLSID\{4454DA96-B29B-C14C-A1B5-AF43D386B909}\11440392
    • CW1


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