Analysis by: Sammy Chua
ALIASES:

Trojan.Win32.Dllhijack.d (Kaspersky); Troj/Agent-ANKX (Sophos)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 56,832 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 13 Aug 2015
Payload: Connects to URLs/IPs, Downloads files, Steals information

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.

Dropping Routine

This Trojan drops the following files wherein it saves the information it gathers:

  • %User Temp%\CVR116B.tmp.cvr -> contains current date
  • %User Temp%\CVR08E6.tmp.cvr -> contains status/error code of HTTP request

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Download Routine

This Trojan connects to the following URL(s) to download its configuration file:

  • http://trim.{BLOCKED}cry.com/news/page{id}.html

It saves the files it downloads using the following names:

  • %User Temp%\CVRA71A.tmp.cvr

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

As of this writing, the said sites are inaccessible.

Information Theft

This Trojan gathers the following data:

  • System Date
  • unique identifier from host name

Other Details

This Trojan requires the following additional components to properly run:

  • {malware path}\iusb3mon.dat -> also detected as TROJ_CIVIRDAT.D

NOTES:

The downloaded configuration file contains the following information:

  • URL of an encrypted file to be downloaded
  • where the encrypted file will be saved
  • where the decrypted file will be saved
  • where a copy of the executed file will be saved

It executes the downloaded file after decryption.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.868.02
FIRST VSAPI PATTERN DATE: 21 Aug 2015
VSAPI OPR PATTERN File: 11.869.00
VSAPI OPR PATTERN Date: 22 Aug 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product and note files detected as TROJ_CIVIRDAT.D

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete the files detected as TROJ_CIVIRDAT.D

*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 File name* 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.
    *Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012 (R2):

  1. Open a Windows Explorer window.
    • For Windows Vista, 7, and Server 2008 users, click Start>Computer.
    • For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen,then click File Explorer.
  2. In the Search Computer/This PC input box, type the name of the file that was detected earlier.
  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 6

Search and delete this file

[ Learn More ]
There may be some 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%\CVR116B.tmp.cvr
  • %User Temp%\CVR08E6.tmp.cvr
  • %User Temp%\CVRA71A.tmp.cvr
  • {malware path}\iusb3mon.dat

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CIVIRDAT.D. 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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