Analysis by: Sabrina Lei Sioting
ALIASES:

TrojanDownloader:Win32/Redonc.A [Microsoft]; Downloader.Trojan [Symantec]; W32/UTOTI.GHS!worm [Fortinet]; Win32/AutoRun.AutoHK.J worm [Nod32]

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm arrives by connecting affected removable drives to a system. 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.

  TECHNICAL DETAILS

File Size: 209,278 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Sep 2010

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Propagation

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

  • {random}.exe

It 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:

;{garbage}
[AutoRun]
;{garbage}
open={random}.exe
;{garbage}
shell\open\Command={random}.exe
;{garbage}
shell\open\Default=1
;{garbage}
shell\explore\Command={random}.exe
;{garbage}

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 7.476.11
FIRST VSAPI PATTERN DATE: 20 Sep 2010
VSAPI OPR PATTERN File: 7.477.00
VSAPI OPR PATTERN Date: 21 Sep 2010

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Search and delete AUTORUN.INF files created by WORM_UTOTI.GHS that contain these strings

[ Learn More ]
 ;{garbage}
[AutoRun]
;{garbage}
open={random}.exe
;{garbage}
shell\open\Command={random}.exe
;{garbage}
shell\open\Default=1
;{garbage}
shell\explore\Command={random}.exe
;{garbage}

Step 3

Scan your computer with your Trend Micro product to delete files detected as WORM_UTOTI.GHS. 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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