Analysis by: Nikko Tamana
ALIASES:

Riskware/Deleter (Fortinet)

 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: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

It does not have any propagation routine.

It does not have any backdoor routine.

It does not drop any other file.

It does not have any downloading capability.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size: 1,269,248 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Jun 2013

Arrival Details

This Trojan 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 Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Dropping Routine

This Trojan does not drop any other file.

Download Routine

This Trojan does not have any downloading capability.

Information Theft

This Trojan does not have any information-stealing capability.

NOTES:

This malware disables the following related antivirus files when found:

  • %Program Files%\AVAST Software\Avast\AvastSvc.exe
  • %Program Files%\AVG\AVG2013\avgwdsvc.exe
  • %Program Files%\AVG\AVG2013\avgcsrvx.exe
  • %Program Files%\AVG\AVG2013\avgrsx.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It disables the said antivirus related files by modifying the access control of the folder and the file it contains.

It modifies the access control to deny access to all users.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.972.05
FIRST VSAPI PATTERN DATE: 10 Jun 2013
VSAPI OPR PATTERN File: 9.973.00
VSAPI OPR PATTERN Date: 11 Jun 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

Scan your computer with your Trend Micro product and note files detected as TROJ_KILLAV.DFA

Step 3

Terminate a process file/s detected as TROJ_KILLAV.DFA

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

Step 4

Search and delete the files detected as TROJ_KILLAV.DFA

*Note: Some component files may be 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.

To stop the malware/grayware from running when certain files are opened:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Right-click Start then click Search....
  2. In the Named input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.

For Windows Vista and Windows 7:

  1. Click Start>Computer.
  2. In the Search Computer input box, type the name of the file detected earlier, and press Enter.
  3. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: Read the following Microsoft page if these steps do not work on Windows 7.

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_KILLAV.DFA. 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.

NOTES:

To restore access to antivirus related files:

  1. Open a command prompt.
    • For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Search box, type CMD then press Enter.
    • For Windows Vista and Windows 7 users, click Start, type CMD in the Search input field then press Enter.
  2. In the CMD console, type the following:


    cacls "%Program Files%\AVAST Software\Avast" /G everyone
    cacls "%Program Files%\AVAST Software\Avast\AvastSvc.exe" /G everyone
    cacls "%Program Files%\AVG\AVG2013" /G everyone
    cacls "%Program Files%\AVG\AVG2013\avgwdsvc.exe" /G everyone
    cacls "%Program Files%\AVG\AVG2013\avgcsrvx.exe" /G everyone
    cacls "%Program Files%\AVG\AVG2013\avgrsx.exe" /G everyone


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