WORM_AUTORUN.SLSU

 Analysis by: John Anthony Banes

 ALIASES:

Worm:Win32/Renocide.gen!A (Microsoft); W32.Harakit (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

507,894 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Mar 2018

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:

  • %User Temp%\suicide.bat
  • %User Temp%\~ip.tmp
  • {drive letter}:\khq

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • %System%\csrcs.exe

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = "%System%\csrcs.exe "

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe csrcs.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This Worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
dreg = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
exp1 = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
fix = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
fix1 = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
ilop = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
regexp = -0.967250588273882

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

Propagation

This Worm drops the following copy(ies) of itself in all removable drives:

  • {drive letter}:\{random file name}.exe

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

Other Details

This Worm connects to the following possibly malicious URL:

  • http://www.{BLOCKED}myip.com/automation/n09230945.asp
  • http://{BLOCKED}p.dyndns.org/?rnd1=47720.7574846551&rnd2=58040.3378566974
  • http://{BLOCKED}u.{BLOCKED}atama.com:88/suturu3.gif
  • http://{BLOCKED}u.{BLOCKED}r.tp:88/shinde3.gif
  • http://{BLOCKED}ro.{BLOCKED}r.tp:88/chinlin3.gif

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

14.126.02

FIRST VSAPI PATTERN DATE:

13 Mar 2018

VSAPI OPR PATTERN File:

14.127.00

VSAPI OPR PATTERN Date:

14 Mar 2018

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

Identify and delete files detected as WORM_AUTORUN.SLSU using the Recovery Console

[ 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\SOFTWARE\Microsoft\DRM
    • amty
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\policies\Explorer
    • Run

Step 5

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_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty
    • dreg = {hex values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty
    • exp1 = {hex values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty
    • fix = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty
    • fix1 = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty
    • ilop = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty
    • regexp = -0.967250588273882

Step 6

Restore this modified registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: SuperHidden = 0
      To: SuperHidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: ShowSuperHidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = 2
      To: Hidden = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe csrcs.exe"
      To: Shell = "Explorer.exe"

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.  
  • %User Temp%\suicide.bat
  • %User Temp%\~ip.tmp
  • {drive letter}:\khq

Step 8

Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.SLSU. 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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