WORM_HANCITOR.YYSVJ

 Analysis by: Ryan Paolo Maglaque

 ALIASES:

Trojan.Win32.Zlader.f(Kaspersky); Win32/Zlader.L trojan(Eset Nod32)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet, Propagates via flashdrives


This worm arrives via removable drives. 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 modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information. It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

88,064 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

25 Jul 2016

Payload:

Connects to URLs/IPs, Executes files, Drops files

Arrival Details

This worm arrives via removable drives.

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 worm drops the following files:

  • {Removable Drive Letter}:\{Shortcut files with the filename of every folder in the removable drive}
    • The malware creates these shortcut files in order to trick the user due to its folder icon and legit filenames.
    • The target path of these shortcuts is set to: %System%\cmd.exe /C ""$RECYCLE.BIN.{GUID}\{GUID}.{pif/cmd}"&& explorer "{GUID folder name - where the original files are stored}""

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It injects codes into the following process(es):

  • iexplore.exe - for Windows 7
  • explorer.exe
  • svchost.exe - for Windows XP

Other System Modifications

This worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows
{Default} = {Random Value}

(Note: The default value data of the said registry entry is {value not set}.)

Propagation

This worm creates the following folders in all removable drives:

  • {Removable Drive Letter}:\$RECYCLE.BIN.{GUID} -> set attributes to Hidden

It drops copies of itself in the following drives:

  • {Removable Drive Letter}:\$RECYCLE.BIN.{GUID}\{GUID}.{pif/cmd} -> Sets attribute to Hidden

Web Browser Home Page and Search Page Modification

This worm modifies the Internet Explorer Zone Settings.

Other Details

This worm connects to the following website to send and receive information:

  • http://{BLOCKED}oldhin.com:80/h/gate.php
  • http://{BLOCKED}iho.ru:80/h/gate.php
  • http://{BLOCKED}etot.ru:80/h/gate.php

It does the following:

  • The injected process iexplore.exe execute the following commands:
    • vssadmin.exe delete shadows /all /quiet
    • bcdedit /set {default} recoveryenabled no
    • bcdedit /set {default} bootstatuspolicy ignoreallfailures
  • It renames all the original folders in Removable Drives to: {Removable Drive Letter}:\{random GUIDs}
    • Attributes of these folders are set to Hidden
  • It stops and disables the following windows components by using the following commands
    • cmd.exe /c net stop SharedAccess - for Windows XP
    • cmd.exe /c sc config SharedAccess start= disabled - for Windows XP
    • cmd.exe /c net stop MpsSvc - for Windows 7
    • cmd.exe /c sc config MpsSvc start= disabled - for Windows 7
    • cmd.exe /c net stop WinDefend - for Windows 7
    • cmd.exe /c sc config WinDefend start= disabled - for Windows 7
    • cmd.exe /c net stop wscsvc
    • cmd.exe /c sc config wscsvc start= disabled
    • cmd.exe /c net stop wuauserv
    • cmd.exe /c sc config wuauserv start= disabled
  • It creates .LNK (shortcut) files using folder names found in removable drives. It then hides the original folders tricking users to click .LNK files. This .LNK files point out to a dropped copy of itself in the removable drive.

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

12.674.08

FIRST VSAPI PATTERN DATE:

25 Jul 2016

VSAPI OPR PATTERN File:

12.675.00

VSAPI OPR PATTERN Date:

26 Jul 2016

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restore this modified 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
    • {Default} = {Random Value}

Step 4

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.
  • {Removable Drive Letter}:\$RECYCLE.BIN.{GUID}

Step 5

Search and delete this file

[ 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.
  • {Removable Drive Letter}:\{Shortcut files with the filename of every folder in the removable drive}

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_HANCITOR.YYSVJ. 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

Reset Internet security settings

[ Learn More ]

NOTES:

To retrieve the original files in the removable drive, kindly follow these steps:

    1. In the Start Menu, search for the Folder Options, then in View Tab of the Folder Options window, select Show hidden files, folders, and drives, then uncheck the Hide protected operating system files checkbox. Click OK.

    2. Go to infected Removable Drive Path.

    3. Right-click each HIDDEN folder with a {GUID} filename, then click Properties. Uncheck the Hidden checkbox.

    4. Rename each folder (with a {GUID} folder name) to their appropriate/correct folder name.


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