BKDR_ZURGOP.A

 Analysis by: Mark Joseph Manahan

 ALIASES:

Trojan-Dropper.Win32.Injector.heay (Kaspersky)

 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:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

163,880 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Feb 2013

Payload:

Collects system information, Connects to URLs/IPs, Downloads files

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:

  • %Application Data%\{random}\{random}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It adds the following processes:

  • svchost.exe

It creates the following folders:

  • %Application Data%\{random}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • {Generated Sha1 Hash}

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
{Random Installed Application Name} = %Application Data%\{random}\{random}.exe

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download and execute arbitrary files (Plugins)
  • Update Itself

It connects to the following websites to send and receive information:

  • http://{BLOCKED}ismcanarium.ru/index.php
  • http://{BLOCKED}wight.ru/index.php

Information Theft

This backdoor gathers the following data:

  • Auto-run Registries
  • Installed Applications
  • OS Version
  • Volume Information

NOTES:
Running Conditions:

Filename is not equal to:

  • Sample

No Virtualization Used (based on registries):

  • Qemu (Quick Emulator)
  • VMware (VMWare)
  • Virtual (VirtualBox)

No Loaded Modules:

  • dbghelp (OllyDbg)
  • sbiedll (SandBox)

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.724.02

FIRST VSAPI PATTERN DATE:

13 Feb 2013

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

Scan your computer with your Trend Micro product and note files detected as BKDR_ZURGOP.A

Step 3

Restart in Safe Mode

[ Learn More ]

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
    • {Random Installed Application Name} = %Application Data%\{random}\{random}.exe

Step 5

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.
  • %Application Data%\{random}

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZURGOP.A. 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.


Did this description help? Tell us how we did.