Modified by: Rika Joi Gregorio

ALIASES:

Trojan:Win32/Napolar.A (Microsoft); Trojan-FDFI!65F9EBFB64CD (McAfee); Trojan.Zbot (Symantec); Trojan.Win32.Cossta.aago (Kaspersky); Troj/Agent-AEKL (Sophos); Trojan.Win32.Napolar.aa (v) (Sunbelt); Trojan horse Generic35.AZBI (AVG)

 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: No

  • In the wild: Yes

  OVERVIEW

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

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 executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 95,232 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Jan 2014
Payload: Compromises system security, Connects to URLs/IPs, Steals information

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.

Installation

This backdoor injects codes into the following process(es):

  • explorer.exe
  • iexplore.exe

Autostart Technique

This backdoor drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\lsass.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Backdoor Routine

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

  • Steal information from a browser
  • Open a browser and load a specific page
  • Run a Tor service
  • Download and execute file
  • Update itself
  • Perform DDOS attack
  • Serves as a SOCKS proxy server

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

  • http://{BLOCKED}.{BLOCKED}.101.90/solar/index.php

However, as of this writing, the said sites are inaccessible.

Information Theft

This backdoor gathers the following data:

  • User name
  • Computer name
  • OS version
  • System type (whether running on a 32-bit or 64-bit system)

Stolen Information

This backdoor sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}.{BLOCKED}.101.90/solar/index.php?v={malware version}&u={user name}&c={computer name}&s={unique identifier}&w={OS version}&b={system type}

NOTES:

This backdoor creates the following named pipe:

  • \\.\pipe\napSolar

It runs a Tor service by dropping the following files:

  • %Application Data%\tor.bin
  • %Application Data%\torrc

It hooks APIs.

With its rootkit functionality, it can block changes to the following registry keys:


Microsoft\Windows\CurrentVersion\Run
Microsoft\Windows NT\CurrentVersion\Windows\run
Microsoft\Windows NT\CurrentVersion\Windows\load
Microsoft\Windows\CurrentVersion\Policies\Explorer\run
Microsoft\Windows NT\CurrentVersion\Winlogon
Microsoft\Active Setup\Installed Components

  SOLUTION

Minimum Scan Engine: 9.700

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

Restart in Safe Mode

[ Learn More ]

Step 3

Search and delete this file

[ 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.
  • %Application Data%\tor.bin
  • %Application Data%\torrc

Step 4

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