Analysis by: Mark Joseph Manahan
ALIASES:

Backdoor:Win32/Cyspetel.A (Microsoft), a variant of Win32/Cyspetel.A trojan (Eset), Generic BackDoor!1y (McAfee), Backdoor.Win32.Cyspetel (Ikarus), W32/Cyspetel.AB!tr (Fortinet)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

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 connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 307,200 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Nov 2012
Payload: Compromises system security

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.

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Primarsoft\
RenkoServ
pdata = "82000d9c"

HKEY_LOCAL_MACHINE\SOFTWARE\Primarsoft\
RenkoServ
edata = "82665e18"

HKEY_LOCAL_MACHINE\SOFTWARE\Primarsoft\
RenkoServ
tdata = "aa5ff081"

HKEY_LOCAL_MACHINE\SOFTWARE\Primarsoft\
RenkoServ
key = "{hex values}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
ImagePath = "{malware path and filename}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
DisplayName = "DLSProvider"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
ErrorControl = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
Type = "10"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\DLSProvider
Description = "Provides network lookup service and enhances data transfer rate."

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_DLSPROVIDER\
0000
Service = "DLSProvider"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_DLSPROVIDER\
0000
ClassGUID = "{8ECC055D-047F-11D1-A537-0000F8753ED1}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_DLSPROVIDER\
0000
DeviceDesc = "DLSProvider"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_DLSPROVIDER\
0000\Control
ActiveService = "DLSProvider"

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

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DLSProvider

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DLSProvider\Security

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_DLSPROVIDER

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_DLSPROVIDER\
0000

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DLSProvider\Enum

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_DLSPROVIDER\
0000\Control

HKEY_LOCAL_MACHINE\SOFTWARE\Primarsoft

HKEY_LOCAL_MACHINE\SOFTWARE\Primarsoft\
RenkoServ

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

  • http://{BLOCKED}tarts.cc/data.php
  • http://{BLOCKED}tarts.cc/reply.php

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.538.03
FIRST VSAPI PATTERN DATE: 20 Nov 2012
VSAPI OPR PATTERN File: 9.539.00
VSAPI OPR PATTERN Date: 21 Nov 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

Restart in Safe Mode

[ Learn More ]

Step 3

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_LOCAL_MACHINE\SOFTWARE
    • Primarsoft
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root
    • LEGACY_DLSPROVIDER
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services
    • DLSProvider

Step 4

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