Analysis by: RonJay Kristoffer Caragay
ALIASES:

Backdoor:Win32/Kelihos!rfn (Microsoft); Mal/Kelihos-B (Sophos); Backdoor.Win32.Hlux.csl (Kaspersky);

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size: 1463,808 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 09 Jun 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.

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
NetworkSaver = "{malware path and file name}"

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}9.10.151.10/start.htm
  • {BLOCKED}1.173.204.165/online.htm
  • {BLOCKED}1.173.204.165/start.htm
  • {BLOCKED}8.158.179.254/online.htm
  • {BLOCKED}7.241.64.208/search.htm
  • {BLOCKED}7.241.64.208/start.htm
  • {BLOCKED}8.240.57.231/default.htm
  • {BLOCKED}2.168.75.128/default.htm
  • {BLOCKED}2.168.75.128/home.htm
  • {BLOCKED}2.168.75.128/index.htm
  • {BLOCKED}2.168.75.128/login.htm
  • {BLOCKED}2.168.75.128/online.htm
  • {BLOCKED}2.168.75.128/search.htm
  • {BLOCKED}2.168.75.128/setup.htm
  • {BLOCKED}2.168.75.128/start.htm
  • {BLOCKED}.170.130.120/index.htm
  • {BLOCKED}.170.153.138/search.htm
  • {BLOCKED}.164.191.201/index.htm
  • {BLOCKED}.139.188.197/start.htm
  • {BLOCKED}.180.213.89/setup.htm
  • {BLOCKED}rodkoff.com/home.htm
  • {BLOCKED}rodkoff.com/login.htm

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.720.07
FIRST VSAPI PATTERN DATE: 03 Jun 2015
VSAPI OPR PATTERN File: 11.721.00
VSAPI OPR PATTERN Date: 03 Jun 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

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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ 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.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • NetworkSaver = "{malware path and file name}"

Step 5

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

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_KELIHOS.SMO. 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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