Analysis by: Sammy Chua
ALIASES:

Trojan.Win32.Yakes.ilkh (Kaspersky); Suspicious.Cloud.5 (Symantec); Win32/Cryptor (AVG)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be dropped by other malware.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 446,464 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 15 Jan 2015
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It may be dropped by the following malware:

  • TROJ_DROPR.GTK

Installation

This spyware drops the following files:

  • %User Temp%\~{number}.tmp - deleted afterwards

(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.)

Other System Modifications

This spyware adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
EventSubSystem

Other Details

This spyware deletes the initially executed copy of itself

NOTES:

This spyware executes the following command:

CMD /C SYSTEMINFO & SYSTEMINFO & SYSTEMINFO & SYSTEMINFO &SYSTEMINFO & DEL {original malware copy}

It reports to the following URL:

  • http://{BLOCKED}.{BLOCKED}.166.33/report_{OS architecture,OS version,computer name, User name, location and filename of the malware, list of running processes}

It downloads from the following URLs:

  • http://{BLOCKED}npost.org/uploads/9d230c34fd5ce3bcb662df94b494116c.png
  • http://www.{BLOCKED}up.net/?id=1514212220516

It connects to the following URLs, all of which are inaccessible as of this writing:

  • http://{BLOCKED}.{BLOCEKD}.233.16/file/photos?handle=68990077
  • http://bpp.{BLOCKED}ma.com/calibre/view?present=0987667
  • http://reader.{BLOCKED}ademyinc.com/encourage/help?pointed=855444
  • http://deid.{BLOCKED}ans.org/calibre/view?present=0987667
  • http://cod.{BLOCKED}mone971.com/encourage/help?pointed=855444

This malware relies on steganography to evade detection. It connects to specific URLs to download a stock image, where majority of its routines are embedded. It then extracts the following from the downloaded image:

  • Arbitrary code
  • List of URLs to be accessed

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.440.04
FIRST VSAPI PATTERN DATE: 27 Jan 2014
VSAPI OPR PATTERN File: 11.441.00
VSAPI OPR PATTERN Date: 28 Jan 2014

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

Restart in Safe Mode

[ Learn More ]

Step 4

Scan your computer with your Trend Micro product to delete files detected as TSPY_GATAK.GTK. 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 5

Search and delete these files

[ 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%\~{number}.tmp

Step 6

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • In HKEY_CURRENT_USER\Software\Microsoft
    • EventSubSystem

Step 7

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