Analysis by: JessaD
ALIASES:

W32/Bamital.j (Mcafee), VirTool:Win32/Injector.gen!BB (Microsoft)

 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

It opens a hidden instance of svchost.exe and injects codes in it. Once it has passed its code of execution to svchost.exe, it sleeps for 1000 milliseconds and delete its physical copy to prevent early detection.

It attempts to access sites.

Once connection is successful, it downloads files from these sites. However, it disregards the file when its size is less than 400H bytes. Otherwise, it reads and decrypts its contents.

This Trojan may be downloaded by other malware/grayware/spyware from remote sites. It may be dropped by other malware.

As of this writing, the said sites are inaccessible.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 29,184 bytes
File Type: PE
File Compression: UPX
Memory Resident: Yes
Initial Samples Received Date: 14 Jan 2011
Payload: Downloads files

Arrival Details

This Trojan may be downloaded by other malware/grayware/spyware from remote sites.

It may be dropped by other malware.

Download Routine

As of this writing, the said sites are inaccessible.

Other Details

This Trojan does the following:

  • It opens a hidden instance of svchost.exe and injects codes in it. Once it has passed its code of execution to svchost.exe, it sleeps for 1000 milliseconds and deletes its physical copy to prevent early detection. Using the value Our_Agent as its User Agent, it attempts to access the following sites:
    • http://{BLOCKED}x.net/wxp/load.php?file=ftpgrabber
    • http://{BLOCKED}x.net/wxp/load.php?file=pokergrabber
  • Once connection is successful, it downloads files from these sites. However, it disregards the file when its size is less than 400H bytes. Otherwise, it reads and decrypts its contents.

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.766.18
VSAPI PATTERN Date: 14 Jan 2011
VSAPI PATTERN Date: 1/14/2011 12:00:00 AM

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

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_INJECT.XSI. 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 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_INJECT.XSI. 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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