BKDR_TERVA.ZRO

May 30, 2014
 Analysis by: Adrian Cofreros
 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:

  • In the wild: Yes

  OVERVIEW

This backdoor may arrive bundled with malware packages as a malware component. It 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.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

90,112 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

30 May 2014

Payload:

Collects system information

Arrival Details

This backdoor may arrive bundled with malware packages as a malware component.

It 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 creates the following folders:

  • %Application Data%\Microsoft\Plugins

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • Download and execute arbitrary files
  • Perform remote shell commands
  • Execute and terminate processes
  • Execute and terminate threads and events
  • Enumerate files

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

  • {BLOCKED}ab.{BLOCKED}hom.com:443

As of this writing, the said sites are inaccessible.

Information Theft

This backdoor retrieves the following information from the affected system:

  • Host name
  • Operating system information
  • Drive information (type, free space)
  • Processor information

NOTES:

It looks for the existence of the following file:

  • %Application Data%\Microsoft\Plugins\ntuser.n1s - Proxy Configuration File

This backdoor use the proxy settings in the file ntuser.n1s to connect to its C&C server.

If ntuser.n1s does not exist, this backdoor use the proxy settings of a user of the computer by checking the following registry values:

HKEY_USERS\{SID}\Software\Microsoft\Windows\CurrentVersion\Internet Settings
ProxyEnable

HKEY_USERS\{SID}\Software\Microsoft\Windows\CurrentVersion\Internet Settings
ProxyServer

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.804.07

FIRST VSAPI PATTERN DATE:

20 May 2014

VSAPI OPR PATTERN File:

10.805.00

VSAPI OPR PATTERN Date:

20 May 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

Identify and terminate files detected as BKDR_TERVA.ZRO

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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.
  • %Application Data%\Microsoft\Plugins

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_TERVA.ZRO. 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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