BKDR_ZEGOST.AE

 Analysis by: Sabrina Lei Sioting
 Modified by: Mark Joseph Manahan

 ALIASES:

a variant of Win32/Farfli.YQ trojan (Eset), Trojan.Win32.Jorik.Zegost.kbn (Kaspersky), Backdoor.Win32.Hupigon (v) (Sunbelt

 PLATFORM:

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

Spammed via email, Downloaded from the Internet, Dropped by other malware

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It 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 then deletes itself afterward.

It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

  TECHNICAL DETAILS

File Size:

207,972 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Apr 2013

Payload:

Compromises system security, Connects to URLs/IPs, Logs keystrokes, Terminates processes

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 and executes them:

  • %Program Files%\Ruopoq Ikgew\Qxtikks.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%\Ruopoq Ikgew

(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 executes then deletes itself afterward.

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
ImagePath = "%Program Files%\Ruopoq lkgew\Qxtikks.exe"

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

  • 12345
  • 12346
  • 12347
  • 12348
  • 12349

It executes the following command(s) from a remote malicious user:

  • Screen Capture
  • Record audio and webcam video
  • List, Create and Delete Services
  • Start/Stop services
  • Log keyboard and mouse activities
  • Perform remote shell
  • Search/Manipulate Files
  • Get System Information

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}.{BLOCKED}.23.77

Process Termination

This backdoor terminates the following processes if found running in the affected system's memory:

  • 360tray.exe
  • avp.exe
  • KvMonXP.exe
  • RavMonD.exe
  • 360sd.exe
  • Mcshield.exe
  • egui.exe
  • NOD32
  • kxetray.exe
  • knsdtray.exe
  • TMBMSRV.exe
  • avcenter.exe
  • ashDisp.exe
  • Avast

Download Routine

This backdoor connects to the following URL(s) to download its configuration file:

  • http://{BLOCKED}r.{BLOCKED}e.qq.com/946851661
  • http://{BLOCKED}r.{BLOCKED}6.tk
  • http://{BLOCKED}s.{BLOCKED}8.com

Information Theft

This backdoor s configuration file contains the following information:

  • C&C Server / URL title of accessed URL

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.838.03

FIRST VSAPI PATTERN DATE:

05 Apr 2013

VSAPI OPR PATTERN File:

9.839.00

VSAPI OPR PATTERN Date:

06 Apr 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_ZEGOST.AE

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • {random}

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%\Ruopoq Ikgew

Step 6

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