Analysis by: Alvin John Nieto
 ALIASES:

Backdoor.Win32.Androm.bmvm (Kaspersky), Worm:Win32/Gamarue.I (Microsoft), Win32/TrojanDownloader.Wauchos.Z trojan (ESET)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • 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

Tipo de compactação: 143,360 bytes
Tipo de arquivo: EXE
Residente na memória: Yes
Data de recebimento das amostras iniciais: 04 Feb 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:

  • %AllUsersProfile%\explorer.exe
  • %AllUsersProfile%\ms{random string}.exe

It adds the following processes:

  • %System%\msiexec.exe

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
540 = "%AllUsersProfile%\ms{random string}.exe"

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}versen.ru/new2/gate.php
  • http://{BLOCKED}ncodes.ru/new2/gate.php
  • http://{BLOCKED}sdietz.ru/new2/gate.php
  • http://{BLOCKED}g.ru/new2/gate.php
  • http://{BLOCKED}s.su/new2/gate.php
  • http://{BLOCKED}ons.ru/new2/gate.php
  • http://{BLOCKED}gin.su/new2/gate.php
  • http://{BLOCKED}all.ru/new2/gate.php
  • http://{BLOCKED}su.su/new2/gate.php
  • http://{BLOCKED}ors.ru/new2/gate.php
  • http://{BLOCKED}or.su/new2/gate.php
  • http://{BLOCKED}not.ru/new2/gate.php
  • http://{BLOCKED}k.su/new2/gate.php

  SOLUTION

Mecanismo de varredura mínima: 9.700
Primeiro arquivo padrão VSAPI: 10.584.05
Data do lançamento do primeiro padrão VSAPI: 04 Feb 2014
VSAPI OPR Pattern Version: 10.585.00
VSAPI OPR Pattern veröffentlicht am: 05 Feb 2014

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 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\policies\Explorer\Run
    • 540 = "%AllUsersProfile%\ms{random string}.exe"

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_ANDROM.NER. 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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