Analysis by: Alvin John Nieto
ALIASES:

Win32/Kryptik.BVHI trojan (ESET), TrojanDownloader:Win32/Nymaim.C (Microsoft), Trojan.Win32.Sharik.rql (Kaspersky), W32/Sharik.BVHI!tr (Fortinet)

 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: 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.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 360,448 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 14 Apr 2014

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 file(s)/component(s):

  • %All Users Profile%\Application Data\lqch\jcmc.hur
  • %All Users Profile%\Application Data\liktr\fmgo.qkj
  • %All Users Profile%\Application Data\qjk\eatguxr.ffk
  • %Windows%\xzlj.zxt
  • %ProgramData%\esve\tblilvl.hgg
  • %ProgramData%\lwfrvy\ktqjrxx.bid

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.. %Windows% is the Windows folder, which is usually C:\Windows.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).)

It drops the following copies of itself into the affected system:

  • %ProgramData%\yakigb\uopyi.exe
  • %ProgramData%\rueo\lgtoy.exe
  • %All Users Profile%\Application Data\htcwgp\hoeba.exe
  • %All Users Profile%\Application Data\afefakr\cvqby.exe

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).. %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
5ongh1 = "%All Users Profile%\Application Data\htcwgp\hoeba.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "%All Users Profile%\Application Data\afefakr\cvqby.exe,explorer.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "%ProgramData%\rueo\lgtoy.exe,explorer.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
lgrh = "%ProgramData%\yakigb\uopyi.exe"

Other Details

This Trojan connects to the following URL(s) to check for an Internet connection:

  • google.com
  • microsoft.com

It connects to the following possibly malicious URL:

  • {BLOCKED}sexwithjimmy.org
  • {random-generated URL}.ru
  • {random-generated URL}.org
  • {random-generated URL}.com
  • {random-generated URL}.net
  • {random-generated URL}.info

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.734.02
FIRST VSAPI PATTERN DATE: 18 Apr 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_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • shell = "%ProgramData%\rueo\lgtoy.exe,explorer.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • shell = "%All Users Profile%\Application Data\afefakr\cvqby.exe,explorer.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • lgrh = "%ProgramData%\yakigb\uopyi.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • 5ongh1 = "%All Users Profile%\Application Data\htcwgp\hoeba.exe"

Step 4

Search and delete these files

[ Learn More ]
There may be some files 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.
  • %All Users Profile%\Application Data\lqch\jcmc.hur
  • %All Users Profile%\Application Data\liktr\fmgo.qkj
  • %All Users Profile%\Application Data\qjk\eatguxr.ffk
  • %Windows%\xzlj.zxt
  • %ProgramData%\esve\tblilvl.hgg
  • %ProgramData%\lwfrvy\ktqjrxx.bid

Step 5

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