Analysis by: Byron Jon Gelera

ALIASES:

Win32/AutoRun.EL (ESET-NOD32); Worm.Win32.AutoRun.EL (Comodo)

 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 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.

  TECHNICAL DETAILS

File Size: 128,512 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 22 Dec 2016

Arrival Details

This worm 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:

  • %System%\SysInfo.dll

(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\Classes\
CLSID\{989D2FEB-5411-4565-8988-1DD2C5263377}\InprocServer32
(Default) = %System%\SysInfo.dll

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{989D2FEB-5411-4565-8988-1DD2C5263377}\InprocServer32
ThreadingModel = Apartment

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{989D2FEB-5411-4565-8988-1DD2C5263377}
(Default) = MyBHO_0.1

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

Propagation

This worm drops the following copy of itself in all physical and removable drives:

  • {Drive Letter}:\SysInfo2.Dll

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

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 6.288.01
FIRST VSAPI PATTERN DATE: 17 Jul 2009
VSAPI OPR PATTERN File: 6.289.00
VSAPI OPR PATTERN Date: 18 Jul 2009

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

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{989D2FEB-5411-4565-8988-1DD2C5263377}\InprocServer32
    • (Default) = %System%\SysInfo.dll
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{989D2FEB-5411-4565-8988-1DD2C5263377}\InprocServer32
    • ThreadingModel = Apartment
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{989D2FEB-5411-4565-8988-1DD2C5263377}
    • (Default) = MyBHO_0.1

Step 5

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • ShowSuperHidden = {user settings}

Step 6

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.
  • {Drive Letter}:\autorun.inf

Step 7

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