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TSPY_POSLOGR.C
Aliases: Trojan:Win32/Malagent!gmb (Microsoft), Trojan.Win32.Bublik.cdfs (Kaspersky)
Malware type: Spyware
Destructive: No
Platform: Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Encrypted: Yes
In the wild: Yes

Overview


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

This malware is involved in the Backoff POS malware attack discovered in August 2014. It has the ability to steal financial information from infected devices. Users who may be affected by this malware may find their financial accounts suddenly being drained of cash.

To get a one-glance comprehensive view of the behavior of this Spyware, refer to the Threat Diagram shown below.

This spyware 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. It connects to a website to send and receive information.

It logs a user's keystrokes to steal information.

Technical Details


File size: 110,592 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 31 Jul 2014
Payload: Connects to URLs/IPs, Compromises system security, Steals information

Arrival Details

This spyware 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 spyware drops the following copies of itself into the affected system:

  • %Application Data%\AdobeFlashPlayer\mswinhost.exe
  • %Application Data%\winserv.exe - deleted afterwards

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It creates the following folders:

  • %Application Data%\AdobeFlashPlayer

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Undsa8301nskal
  • uyhnJmkuTgD

It stays memory-resident by creating remote threads:

  • explorer.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows NT Service = "%Application Data%\AdobeFlashPlayer\mswinhost.exe"

Other System Modifications

This spyware adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
identifier = "{random characters as ID}" such as "GQBViaL"

Backdoor Routine

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

  • Download updated copy
  • Terminate itself
  • Uninstall itself
  • Download and execute arbitrary files
  • Upload log files

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

  • http://{BLOCKED}tp5imap2.com/aero2/fly.php
  • http://{BLOCKED}tp5imap3.com/aero2/fly.php
  • http://{BLOCKED}tp5imap4.ru/aero2/fly.php

Information Theft

This spyware gathers the following data:

  • User name
  • Computer name
  • Malware version name (e.g. backoff)
  • Malware built version (e.g. 1.55)

It logs a user's keystrokes to steal information.

Stolen Information

This spyware saves the stolen information in the following file:

  • %Application Data%\AdobeFlashPlayer\Log.txt - contains logged active window, installations, keystrokes and mouse activities with corresponding date and time

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Other Details

This spyware drops the following file(s)/component(s):

  • %Application Data%\AdobeFlashPlayer\Local.dat - temporarily stores all found track data
  • %Application Data%\mskrnl - encrypted copy of the malware

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

NOTES:

It performs memory scraping on the following processes to check for track data and posts the data to the C&C server:

  • explorer.exe
  • lsass.exe
  • spoolsv.exe
  • mysqld.exe
  • services.exe
  • wmiprvse.exe
  • LogonUI.exe
  • taskhost.exe
  • wuauclt.exe
  • smss.exe
  • csrss.exe
  • winlogon.exe
  • alg.exe
  • iexplore.exe
  • firefox.exe
  • chrome.exe
  • devenv.exe

It posts the following information to the C&C server, where {malware version name} for this variant is backoff and {built version} is 1.55:

  • &op=1&id={identifier found in registry}&ui={username} @ {computer name}&wv={Windows version}&gr={malware version name}&bv={built version}&data={encrypted data}

Solution


Minimum scan engine: 9.700
First VSAPI Pattern File: 10.956.09
First VSAPI Pattern Release Date: 31 Jul 2014
VSAPI OPR Pattern Version: 10.957.00
VSAPI OPR Pattern Release Date: 31 Jul 2014

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • identifier = "{random characters as ID}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Windows NT Service = "%Application Data%\AdobeFlashPlayer\mswinhost.exe"

Step 5

Search and delete these files

[ 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%\AdobeFlashPlayer\Log.txt
  • %Application Data%\AdobeFlashPlayer\Local.dat
  • %Application Data%\mskrnl

Step 6

Search and delete these folders

[ Learn more ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\AdobeFlashPlayer

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_POSLOGR.C. 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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Analysis By: Rhena Inocencio

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