Analysis by: Karen Ivy Titiwa

ALIASES:

Worm:Win32/Hilgild.A (MICROSOFT); Trojan.Win32.Hesv.avgr (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via network shares, Propagates via removable drives

This Worm arrives via removable drives. It arrives by accessing affected shared networks. 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 uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size: 258,048 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 03 Sep 2019
Payload: Steals information

Arrival Details

This Worm arrives via removable drives.

It arrives by accessing affected shared networks.

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 copies of itself into the affected system and executes them:

  • %All Users Profile%\Application Data\wmimgmt.exe

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It drops the following files:

  • %Temporary Internet Files%\s.log
  • %Temporary Internet Files%\t.log
  • %Public%\Documents\Media\line.dat
  • %Public%\Documents\Media\{random}.db
  • %Temporary Internet Files%\sharedir.tmp
  • %Temporary Internet Files%\hostname.tmp → contains host name
  • %Temporary Internet Files%\workgrp.tmp → contains list of connected machine
  • %Temporary Internet Files%\drivers.p → contains list of drive letters
  • %Temporary Internet Files%\INFO.txt → contains list of gathered information
  • %User Temp%\temp.vih → contains list of key, subkeys and values of specified registry keys
  • {Removable drive}:\RECYCLER\desktop.ini
  • {Removable drive}:\~thumbs.tmp
  • {Removable drive}:\RECYCLER\wmimgmt.com

It drops and executes the following files:

  • %Temporary Internet Files%\ghi.bat → contains commands for gathering information
  • %Temporary Internet Files%\avpi.exe

(Note: %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista, 7 and 2008(64-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8, 8.1, 2012(64-bit) and 10(64-bit).)

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

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

  • ProgramLQBMute
  • DB_F_PROTECT

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
wmi32 = %All Users Profile%\Application Data\wmimgmt.exe

Other System Modifications

This Worm deletes the following files:

  • %User Temp%\temp.vih
  • %Temporary Internet Files%\s.log
  • %Temporary Internet Files%\t.log
  • %Temporary Internet Files%\sharedir.tmp
  • %Temporary Internet Files%\hostname.tmp
  • %Temporary Internet Files%\workgrp.tmp
  • %Temporary Internet Files%\drivers.p
  • %Temporary Internet Files%\ghi.bat
  • %Temporary Internet Files%\INFO.txt

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista, 7 and 2008(64-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8, 8.1, 2012(64-bit) and 10(64-bit).)

It modifies the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer
GlobalAssocChangedCounter = {data}

Propagation

This Worm drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

; for 16-bit app support
[extensions]
[fonts]
[mci extensions]
[Mail]
[files]
mpeg=MPEGVideo
snd=atl.dll
wm=mcd32.dll
wma=MP4
wmp=MP3MAPI=1
MAPIX=1
MAPIXVER=1.0.0.1
OLEMessaging=1
CMCDLLNAME32=mapi32.dll
CMC=1
[MCI Extensions]
aif=loghours.dll
aiff=ole2.dll
asf=d3dramp.dll
aifc=psnppagn.dll
asx=MPEGVideo2
mpe=usrdtea.dll
mpg=MPEGVideo
mpv2=idq.dll
wmv=MPEG
wmx=MPEGVideo32
251846kfi56s
;cc30qiLas JdZ3adCjPadf823423423
[Kasasf0q]iLasdfKD28Ls33wDmrq6Jl1EdAf8
;K0qi asfLasmet Ca19lhs ipconfidfjKD28 mpeg Ls33
;8sdaA89K3J0DSKJLG8P4Ld0laH saG
[shellas]dBop1caomasdnhsdf=fdsjsdf.exenghasadnetstad.
as=asdfash0ffsad asd1safsdf9safdasf
;ff0qiLasfJdKPEGVi2412344
oaeFK1Kajkw6DdD3L2f3a31zazi8a135Lwra
Ls33wDm2rqJl31EdAf8soae FK1KajkwDdDLKAl6sdcO7K
asdfs3adfLafdsfadsdm FKaj3kw6Al6sdcO7K
;K0qi65aa3sJZ3adCsa1sdfjKD32asddfasdf
;K0qiLa1Kajkw845rthgK2f33a21zazi8a35Lwra
[ autorun
K0qi3a3dCa19lsdfjKD2asfd323asdfsdfa
PRINT=PRINT.EXE ASDd938daf897asdj
;[asfd3]2KdafjKD2
Play= Copy pictures to a foler on my computer
shEllEXEcuTe = RECyCLER\wmimgmt.com
;8sdaA38G8P343LklJ8ASD FL3333sd0laHsa3G12fgsdsaKd
sheLL\oPeN\coMManD =RECYCLER\wmimgmt.com
;343P5gd2fKgCOMNANDASDF=REC R5gf56sd315eK592AdsSD
;89234SAKDJWKsatyh3adaflk7yas
;343P5F 25F5gf56sd315eK56fs43d4asd56KdaDfs1
shELl\ExpLore\ComMand= RECYCLER\wmimgmt.com
s=asfdsa5dfafdAf8soaeFExpLoreqiLasJ8Z3adC
;89234AKfdk28ASDFsaaty7ysK6DRg if5S3jsHks
Action=Open folder to view files
;8k3kKsafG ASDFdlsflK3a23F4jksfa5F3J90s
;f0PEG3ideoqiLasJd9Z3adCa319lhsdfjKD3223adfasfd
Spell=Take no action then print the picture

[mci]
woafont=app936.FON
EGA40WOA.FON=EGA40WOA.FON
[386enh]
EGA51WOA.FON=KBDDSP.FON
[drivers]
wave=mmdrv.dll
[driver32]
timer=timer.drv

Information Theft

This Worm gathers the following data:

  • list of of the active console code page
  • user account information
  • list of local group administrators
  • list of currently running processes
  • system information
  • list of values in HKEY_CURRENT_USER\Software\Microsoft\Office\{version}\Common\UserInfo
  • list of current TCP/IP network configuration values
  • list of TCP connections
  • list of current ARP entries
  • routing table
  • list of local NetBIOS names
  • list of remote [machine] names and their IP addresses
  • list of services
  • list of network connections
  • list of shared resources
  • list of domains in the network
  • computer name
  • list of files and folders in all drives

Other Details

This Worm adds the following registry keys:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
Browser

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
Browser\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
Browser\Settings

It does the following:

  • Searches for the following running processes
    • ravmond.exe
    • ccenter.exe
    • ravtask.exe
    • op_mon.exe
    • 360tray.exe
    • pctstray.exe
    • avp.exe
    • vsserv.exe
    • v3ltray.exe
    • v3svc.exe
    • ccsvchst.exe.
    • mcagent.exe
    • avguard.exe
    • avastsvc.exe
  • Will not proceed to its worm routine if it finds the following process running in the memory
    • avp.exe
  • It searches for folders in all shared folders and removable drives then drops copies of itself as {folder name}.EXE.
  • It sets the attributes of all the found folders in the shared folders and removable drives to Hidden.
  • Must be in this directory to conduct its worm routine
    • %All Users Profile%\Application Data\wmimgmt.exe

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It deletes the following registry keys that were created during execution:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
Browser\Recent File List

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.344.02
FIRST VSAPI PATTERN DATE: 04 Sep 2019
VSAPI OPR PATTERN File: 15.345.00
VSAPI OPR PATTERN Date: 05 Sep 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Terminate this process

[ Learn More ]

  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
  • %All Users Profile%\Application Data\wmimgmt.exe
  • %Temporary Internet Files%\avpi.exe

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\Run
    • wmi32 = %All Users Profile%\Application Data\wmimgmt.exe

Step 5

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_CURRENT_USER\Software
    • Local AppWizard-Generated Applications

Step 6

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
    • GlobalAssocChangedCounter = from: [data] to: {default}

Step 7

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\wmimgmt.exe
  • %Temporary Internet Files%\s.log
  • %Temporary Internet Files%\t.log
  • %Public%\Documents\Media\line.dat
  • %Public%\Documents\Media\{random}.db
  • %Temporary Internet Files%\sharedir.tmp
  • %Temporary Internet Files%\hostname.tmp
  • %Temporary Internet Files%\workgrp.tmp
  • %Temporary Internet Files%\drivers.p
  • %Temporary Internet Files%\INFO.txt
  • %User Temp%\temp.vih
  • {Removable drive}:\RECYCLER\desktop.ini
  • {Removable drive}:\~thumbs.tmp
  • {Removable drive}:\RECYCLER\wmimgmt.com
  • %Temporary Internet Files%\ghi.bat
  • %Temporary Internet Files%\avpi.exe

Step 8

Search and delete AUTORUN.INF files created by Worm.Win32.HILGILD.A that contain these strings

[ Learn More ]
DATA_GENERIC
  • If the lines are present, delete the file.
  • Repeat steps 3 to 5 for the remaining AUTORUN.INF files in other remaining removable drives.
  • Close Search Results.
  • Step 9

    1. Open a command prompt.
      • For Windows 7 users, click Start, enter CMD in the Find input field, and press Enter.
    2. In the CMD console, enter the following:

      ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][filename] [/S [/D] [/L]]

      Where:
      + Activates an attribute
      - Disables an attribute
      R Read-only file attribute
      A Archive file attribute
      S System file attribute
      H Hidden file attribute
      I Indexed file attribute without content
      [drive:][path][filename]
      Specifies one or more files in the current folder and all its subfolders
      /S Processes the corresponding files in the current folder and all its subfolders
      /D Process folders
      /L Act on the attributes of the symbolic link instrad of the target of the symbolic link
      Example:
      To make all files and folders (including subfolders visible in drive D:
      ATTRIB –H D:\* /S /D
    3. Repeat the step above for folders and files from other drives or directories.

    Step 10

    Scan your computer with your Trend Micro product to delete files detected as Worm.Win32.HILGILD.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 the following Trend Micro Support pages for more information:


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