Analysis by: RonJay Kristoffer Caragay
 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

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

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 207,872 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 Aug 2014
Payload: Connects to URLs/IPs, Steals information

Arrival Details

This backdoor 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 backdoor drops the following non-malicious files:

  • %Application Data%\avetir.exe - copy of %System%\cmd.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • WDaxxxxWWaK

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Start or terminate processes or threads
  • Download and execute arbitrary files
  • Perform remote shell commands
  • Enumerate files and directories
  • Read files
  • Get user name
  • Get computer name
  • Get OS type and version
  • Get processor information
  • Get drive information
  • Get and use proxy settings
  • Sleep for an amount of time

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://sale.{BLOCKED}w.com

As of this writing, the said sites are inaccessible.

Information Theft

This backdoor gathers the following data:

  • User name
  • Computer name
  • OS type and version
  • Processor information
  • Drive information

NOTES:

This backdoor needs the following parameter to run its routine:

  • -mem

It finds a user of the computer that uses a proxy by reading proxy-related registry entries. If it finds one, it uses the user's proxy server settings to connect to its C&C server.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.986.02
FIRST VSAPI PATTERN DATE: 15 Aug 2014
VSAPI OPR PATTERN File: 10.987.00
VSAPI OPR PATTERN Date: 15 Aug 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

Scan your computer with your Trend Micro product and note files detected as BKDR_PROXY.ERM

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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.
  • %Application Data%\avetir.exe

Step 6

Search and delete the files detected as BKDR_PROXY.ERM

*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 Named 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.

For Windows Vista and Windows 7:

  1. Click Start>Computer.
  2. In the Search Computer input box, type the name of the file detected earlier, and press Enter.
  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 7

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