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BKDR_PROXY.APV

January 22, 2015
 Analysis by: Jaime Benigno Reyes
 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


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:

94,208 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

19 Jan 2015

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.

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • list, find, read and get file information
  • list and get drive information
  • delete files
  • start or terminate a process
  • download and execute arbitrary files
  • perform remote shell commands
  • sleep
  • copy %System%\cmd.exe as {folder specified by remote attacker}\slsa.exe
  • copy %System%\ja-JP\cmd.exe.mui as {folder specified by remote attacker}\cmd.exe.mui

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

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

  • www.{BLOCKED}asket.net

As of this writing, the said sites are inaccessible.

Information Theft

This backdoor accepts the following parameters:

  • base64 encoded string containing the username and password of the proxy server of the infected machine separated by a colon

It gathers the following data:

  • operating system
  • host name
  • user name
  • IP address
  • MAC address

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.700

VSAPI OPR PATTERN File:

11.425.00

VSAPI OPR PATTERN Date:

21 Jan 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

Identify and terminate files detected as BKDR_PROXY.APV

[ 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 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.  
  • slsa.exe
  • cmd.exe.mui

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_PROXY.APV. 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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