Analysis by: Rika Joi Gregorio
ALIASES:

Worm:Win32/Dorkbot.AT(Microsoft), W32.IRCBot.BPQ(Norton), Trojan.Win32.Yakes(Ikarus)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via instant messaging applications, Downloaded from the Internet, Dropped by other malware

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.

  TECHNICAL DETAILS

File Size: 69,632 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 21 May 2013
Payload: Connects to URLs/IPs, Sends messages

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

  • {CLSID}

NOTES:

Once executed, it searches for the following processes if running in the system:

  • skype.exe
  • msmsgs.exe
  • msnmsgr.exe
  • qip.exe
  • googletalk.exe

It sends the following shortened links to user's contacts found on the mentioned applications:

  • http://{BLOCKED}o.{BLOCKED}l/ILGdM?foto={email address of receiver}
  • http://{BLOCKED}o.{BLOCKED}l/ILGdM?png={email address of receiver}
  • http://{BLOCKED}o.{BLOCKED}l/wwo7s?fotos={email address of receiver}
  • http://goo.gl/PVwkU?skype={email address of receiver}
  • http://{BLOCKED}o.{BLOCKED}l/WKyb5?profil={email address of receiver}

The URL leads the user to a file uploaded in 4shared. The file is possibly an updated copy of the malware.

However, as of this writing, the account where the file is uploaded is already suspended.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.940.07
FIRST VSAPI PATTERN DATE: 25 May 2013
VSAPI OPR PATTERN File: 9.941.00
VSAPI OPR PATTERN Date: 26 May 2013

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

Identify and terminate files detected as WORM_DORKBOT.QMU

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Scan your computer with your Trend Micro product to delete files detected as WORM_DORKBOT.QMU. 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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