Analysis by: Cris Nowell Pantanilla
ALIASES:

Backdoor.Win32.Sykipot.cw (Kaspersky); Backdoor:Win32/Wkysol.G (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 27,136 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 29 Mar 2012
Payload: Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_INJECT.MCA

Installation

This backdoor is injected into the following processes running in memory:

  • IEXPLORE.EXE

Backdoor Routine

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

  • Download and Upload file
  • Command Shell
  • Create/Terminate Process
  • Create,Open and Delete files

It connects to the following websites to send and receive information:

  • {BLOCKED}tsvilla.coyo.eu

As of this writing, the said sites are inaccessible.

NOTES:

This backdoor gets its settings from the configuration file %Application Data%\Local Settings\setm.ini. The said configuration file contains the URL where this backdoor connects to, as well as the file names of components.

It connects to the site http://{malicious site}/kys_allow_get.asp?name=getkys.jpg&hostname={hostname}-{IP Address} to download a possible configuration file that contains its intended routines. It also sends back information such as host name and IP address to the said site.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.872.01
FIRST VSAPI PATTERN DATE: 29 Mar 2012
VSAPI OPR PATTERN File: 8.873.01
VSAPI OPR PATTERN Date: 30 Mar 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove the malware/grayware file that dropped/downloaded BKDR_WKYSOL.A

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_WKYSOL.A

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete the file detected as BKDR_WKYSOL.A

*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 manually delete a malware/grayware file from the affected system:

  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.

Step 6

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