TROJ_CRYPTOP.KLS

May 26, 2015
 Modified by: Michelle Morales
 ALIASES:

Trojan-Ransom.Win32.Agent.pox (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

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

  TECHNICAL DETAILS

File Size:

4,096 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

12 Feb 2015

Payload:

Connects to URLs/IPs, Displays message/message boxes

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.

Installation

This Trojan drops the following component file(s):

  • C:\tempfile\randseed.bin
  • C:\tempfile\pubring.pgp
  • C:\tempfile\tiso.bat --> this file contains the command line used for extracting downloaded file

It creates the following folders:

  • C:\tempfile

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}ail.com/base.rar
  • http://{BLOCKED}ail.com/rar

It saves the files it downloads using the following names:

  • C:\tempfile\base.rar
  • C:\tempfile\rar.exe --> this is a non-malicious file used for extracting downloaded rar file

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

NOTES:

The malware, upon execution, displays the following messagebox:

The file it downloads, BASE.RAR, is extracted using the dropped batch file TISO.BAT. The batch file contains the following lines:

> rar e -ptisofaraba base.rar

The following files are extracted:

  • mansound.exe - detected as TROJ_GULCRYPT.A
  • mask.win
  • pgp.exe

It then executes the extracted file mansound.exe.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.474.06

FIRST VSAPI PATTERN DATE:

12 Feb 2015

VSAPI OPR PATTERN File:

11.475.00

VSAPI OPR PATTERN Date:

13 Feb 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

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • C:\tempfile

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_CRYPTOP.KLS. 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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