WORM_HANCITOR.YYSVD

July 02, 2016
 Analysis by: Rhena Inocencio
 ALIASES:

Trojan.Win32.Agent.nevzba (Kaspersky), a variant of Win32/Injector.DAQT trojan (ESET)

 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:

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

This worm arrives via removable drives. It may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

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:

71,680 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Jun 2016

Payload:

Drops files, Connects to URLs/IPs

Arrival Details

This worm arrives via removable drives.

It may be dropped by the following malware:

  • W2KM_ZLADER.YYSVD

Installation

This worm injects itself into the following processes as part of its memory residency routine:

  • explorer.exe
  • svchost.exe

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}.{src/pif/cmd} -> Sets attribute to Hidden

Backdoor Routine

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

  • Download a file from a specific URL and inject to svchost.exe
  • Download file from a specific URL and execute it

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}ltontuld.com/h/gate.php

It does the following:

  • 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
    • cmd.exe /c sc config SharedAccess start=disabled
    • 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:

9.800

FIRST VSAPI PATTERN FILE:

12.606.09

FIRST VSAPI PATTERN DATE:

22 Jun 2016

VSAPI OPR PATTERN File:

12.607.00

VSAPI OPR PATTERN Date:

23 Jun 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

Remove the malware/grayware file that dropped/downloaded WORM_HANCITOR.YYSVD. (Note: Please skip this step if the threat(s) listed below have already been removed.)

    • W2KM_ZLADER.YYSVD

Step 4

Restart in Safe Mode

[ Learn More ]

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

Step 6

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

Step 7

Reset Internet security settings

[ Learn More ]

Step 8

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

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. Right-click each HIDDEN folder with a {GUID} filename, then click Properties. Uncheck the Hidden checkbox.
  3. Rename each folder (with a {GUID} folder name) to their appropriate/correct folder name.


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