Analysis by: Christopher Daniel So
ALIASES:

TrojanDownloader:Win32/Chepvil.J (Microsoft), Trojan.FakeAV (Symantec), Trojan-Downloader.Win32.Small.btcy (Kaspersky)

 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 attempts to access Web sites to download files, which are possibly malicious.

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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 16,896 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Mar 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.

Other Details

This Trojan attempts to access the following websites to download files, which are possibly malicious:

  • http://{BLOCKED}.{BLOCKED}.121.33/spm.exe
  • http://{BLOCKED}.{BLOCKED}.35.159/spm.exe
  • http://{BLOCKED}.{BLOCKED}.121.33/lol2.exe
  • http://{BLOCKED}.{BLOCKED}.121.33/pod.exe
  • http://{BLOCKED}.{BLOCKED}.121.33/spm.exe
  • http://{BLOCKED}.{BLOCKED}.35.159/lol2.exe
  • http://{BLOCKED}.{BLOCKED}.35.159/pod.exe
  • http://{BLOCKED}.{BLOCKED}.35.159/spm.exe

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.924.06
FIRST VSAPI PATTERN DATE: 25 Mar 2011

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_CHEPVIL.B

[ 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

Scan your computer with your Trend Micro product to delete files detected as TROJ_CHEPVIL.B. 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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