ALIASES:

TrojanDownloader:Win32/Ufraie.A (Microsoft); Generic Downloader.x!fzw (McAfee); Downloader (Symantec); Trojan-Downloader.Win32.Small.cckc (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 53,248 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 05 Nov 2011

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.

Other System Modifications

This Trojan deletes the following files:

  • faioegoe

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft
kr_done1 = 4eb4b68a

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\kr_done1
  • b

(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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}e.com/
  • http://kokujybeb.{BLOCKED}2.in/t/d2hsdWF3OzJ0OHY5Oj0,cyJtIG8kaUVyam9zeHk9Tn5DSgIRAkxDUU1bFx0CHQAdCQECHQYEDgdEDwgCDA0QDXF5cmUlM3tvJjwmJ2VrPC4jbGJ1MiA1PGVpfC4yNC9iUUcDAAcKEwkcVFpcShlTXkNDQkdMQEBEQF8UGghAT1nk6Oa,tLW,4ri5uru8vb6_oKGiow==/count.htm

It deletes the initially executed copy of itself

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

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_CURRENT_USER\Software\Microsoft
    • kr_done1=4eb4b68a

Step 3

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%\kr_done1
  • b

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_MEREDROP.AW. 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.

Step 5

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again. faioegoe


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