TROJ_FAKEAV.ZZM

 Analysis by: Christopher Daniel So

 ALIASES:

VirusDoctor (Symantec), FraudTool.Win32.SecurityShield.ek!d (Sunbelt), W32/KazyPack.MK!tr (Fortinet)

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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 connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats. It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

332,288 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Feb 2011

Payload:

Downloads files

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.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System Root%\Documents and Settings\All Users\Application Data\{random name}\{random name}.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It drops the following files:

  • %System Root%\Documents and Settings\All Users\Application Data\{random name}\{random name}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\Documents and Settings\All Users\Application Data\{random name}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Download Routine

This Trojan connects to the following malicious URLs:

  • http://{BLOCKED}.{BLOCKED}.53.223/install.php?affid={random number}

It accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}.53.223/lurl.php?affid={random number}
  • http://{BLOCKED}0.xxx.com/{unknown-0}.exe
  • http://{BLOCKED}1.xxx.com/{unknown-1}.exe
  • http://{BLOCKED}2.xxx.com/{unknown-2}.exe
  • http://{BLOCKED}3.xxx.com/{unknown-3}.exe
  • http://{BLOCKED}4.xxx.com/{unknown-4}.exe
  • http://{BLOCKED}5.xxx.com/{unknown-5}.exe
  • http://{BLOCKED}6.xxx.com/{unknown-6}.exe
  • http://{BLOCKED}7.xxx.com/{unknown-7}.exe
  • http://{BLOCKED}8.xxx.com/{unknown-8}.exe
  • http://{BLOCKED}9.xxx.com/{unknown-9}.exe
  • http://{BLOCKED}a.xxx.com/{unknown-10}.exe
  • http://{BLOCKED}b.xxx.com/{unknown-11}.exe
  • http://{BLOCKED}c.xxx.com/{unknown-12}.exe
  • http://{BLOCKED}d.xxx.com/{unknown-13}.exe
  • http://{BLOCKED}e.xxx.com/{unknown-14}.exe
  • http://{BLOCKED}f.xxx.com/{unknown-15}.exe
  • http://{BLOCKED}g.xxx.com/{unknown-16}.exe
  • http://{BLOCKED}h.xxx.com/{unknown-17}.exe

It saves the files it downloads using the following names:

  • %User Temp%\a{random hexadecimal number 1}.tmp
  • %User Temp%\a{random hexadecimal number 2}.tmp
  • %User Temp%\a{random hexadecimal number 3}.tmp
  • %User Temp%\a{random hexadecimal number 4}.tmp
  • %User Temp%\a{random hexadecimal number 5}.tmp
  • %User Temp%\a{random hexadecimal number 6}.tmp
  • %User Temp%\a{random hexadecimal number 7}.tmp
  • %User Temp%\a{random hexadecimal number 8}.tmp
  • %User Temp%\a{random hexadecimal number 9}.tmp
  • %User Temp%\a{random hexadecimal number 10}.tmp
  • %User Temp%\a{random hexadecimal number 11}.tmp
  • %User Temp%\a{random hexadecimal number 12}.tmp
  • %User Temp%\a{random hexadecimal number 13}.tmp
  • %User Temp%\a{random hexadecimal number 14}.tmp
  • %User Temp%\a{random hexadecimal number 15}.tmp
  • %User Temp%\a{random hexadecimal number 16}.tmp
  • %User Temp%\a{random hexadecimal number 17}.tmp
  • %User Temp%\a{random hexadecimal number 18}.tmp
  • %User Temp%\a{random hexadecimal number 19}.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

8.900

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

Identify and terminate files detected as TROJ_FAKEAV.ZZM

[ Learn More ]
  1. 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.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
%System Root%\Documents and Settings\All Users\Application Data\{random name}

Step 4

Search and delete these files

[ Learn More ]
There may be some component 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%\a{random hexadecimal number 1}.tmp
%User Temp%\a{random hexadecimal number 2}.tmp
%User Temp%\a{random hexadecimal number 3}.tmp
%User Temp%\a{random hexadecimal number 4}.tmp
%User Temp%\a{random hexadecimal number 5}.tmp
%User Temp%\a{random hexadecimal number 6}.tmp
%User Temp%\a{random hexadecimal number 7}.tmp
%User Temp%\a{random hexadecimal number 8}.tmp
%User Temp%\a{random hexadecimal number 9}.tmp
%User Temp%\a{random hexadecimal number 10}.tmp
%User Temp%\a{random hexadecimal number 11}.tmp
%User Temp%\a{random hexadecimal number 12}.tmp
%User Temp%\a{random hexadecimal number 13}.tmp
%User Temp%\a{random hexadecimal number 14}.tmp
%User Temp%\a{random hexadecimal number 15}.tmp
%User Temp%\a{random hexadecimal number 16}.tmp
%User Temp%\a{random hexadecimal number 17}.tmp
%User Temp%\a{random hexadecimal number 18}.tmp
%User Temp%\a{random hexadecimal number 19}.tmp

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.ZZM . 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.


Did this description help? Tell us how we did.