TROJ_CRYPCTB.SMD

January 21, 2015
 Analysis by: Rika Joi Gregorio
 ALIASES:

TrojanDownloader:Win32/Dalexis (Microsoft), Downloader.Ponik(Norton), Downloader-FAMV(McAfee), Win32/TrojanDownloader.Elenoocka.A trojan(Eset), Trojan-Downloader.Win32.Upatre(Ikarus)

 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:

Spammed via email

This malware was discovered to be involved in a series of malicious campaigns that found victims in Europe, China, Middle East, Africa, India, and Latin America on late January 2015. It comes as an attachment to a spammed mail and downloads a cryptolocker variant onto affected systems. Users affected by this malware may find their important documents or files unable to be used and/or accessed.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan arrives as an attachment to email messages mass-mailed by other malware/grayware or malicious users.

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

  TECHNICAL DETAILS

File Size:

34,304 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

19 Jan 2015

Payload:

Downloads files

Arrival Details

This Trojan arrives as an attachment to email messages mass-mailed by other malware/grayware or malicious users.

Installation

This Trojan drops the following files:

  • %User Temp%\{malware file name}.rtf
  • %User Temp%\temp_cab_{random digits}.cab

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • {BLOCKED}eedle.com:80/menu_files/pack.tar.gz
  • {BLOCKED}e.asso.fr:80/piwigotest/pack.tar.gz
  • {BLOCKED}sultores.com:80/tmp/pack.tar.gz
  • {BLOCKED}portive-martinique.com:80/wp-includes/pack.tar.gz
  • {BLOCKED}healthtrack.com:80/media/pack.tar.gz
  • {BLOCKED}tem.fr:80/jb/pack.tar.gz
  • {BLOCKED}as-saint-joseph.com:80/css/pack.tar.gz
  • {BLOCKED}t-its.de:80/fit/pack.tar.gz
  • {BLOCKED}u-photographe.com:80/tmp/pack.tar.gz
  • {BLOCKED}dessources.com:80/assets/pack.tar.gz
  • {BLOCKED}edia.org:80/histoiredesarts/pack.tar.gz
  • {BLOCKED}eedle.com:443/menu_files/pack.tar.gz
  • {BLOCKED}e.asso.fr:443/piwigotest/pack.tar.gz
  • {BLOCKED}es.com:443/tmp/pack.tar.gz
  • {BLOCKED}portive-martinique.com:443/wp-includes/pack.tar.gz
  • {BLOCKED}healthtrack.com:443/media/pack.tar.gz
  • {BLOCKED}stem.fr:443/jb/pack.tar.gz
  • {BLOCKED}as-saint-joseph.com:443/css/pack.tar.gz
  • {BLOCKED}ts.de:443/fit/pack.tar.gz
  • {BLOCKED}u-photographe.com:443/tmp/pack.tar.gz
  • {BLOCKED}essources.com:443/assets/pack.tar.gz
  • {BLOCKED}edia.org:443/histoiredesarts/pack.tar.gz

It saves the files it downloads using the following names:

  • %User Temp%\{random digits}.exe - detected as TROJ_CRYPCTB.SME

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

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

NOTES:

Upon execution, it opens its dropped non-malicious file %User Temp%\{malware file name}.rtf to hide its malicious routines from the user.

  SOLUTION

Minimum Scan Engine:

9.700

VSAPI OPR PATTERN File:

11.427.00

VSAPI OPR PATTERN Date:

22 Jan 2015

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Remove malware/grayware files dropped/downloaded by TROJ_CRYPCTB.SMD. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • TROJ_CRYPCTB.SME

Step 4

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%\{malware file name}.rtf
  • %User Temp%\temp_cab_{random digits}.cab

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_CRYPCTB.SMD. 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 the following Trend Micro Support pages for more information:


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