Analysis by: Rheniel Rhay Ramos
ALIASES:

Trojan.Win32.Agentb.bwkq (Kaspersky); TrojanDownloader:Win32/Banload (Microsoft); Trojan.Listrix (Symantec)

 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

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

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 executes then deletes itself afterward.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: 35,840 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 21 Jun 2017
Payload: Drops files

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 files:

  • %User Temp%\{4 random characters}.tmp -> the list of files, will be moved after
  • %Application Data%\Update\Temp\ufiles.txt -> the new name of the tmp file after it is moved

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %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.)

It adds the following processes:

  • cmd.exe /c del {malware path}\{malware name} >> NUL

It executes then deletes itself afterward.

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Other Details

This Trojan does the following:

  • It lists all files in all drives, excluding fixed drives, to the temp file that has the following extensions or contains the string "pass", including the file size and system time it was created:
    • .rtf
    • .zip
    • .pfx
    • .cer
    • .crt
    • .pem
    • .key
    • .cfg
    • .conf
    • .pst
    • .rar
    • .doc
    • .docx
    • .xls
    • .xlsx
    • .pdf
    • .pub
    • .ppk

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.644.05
FIRST VSAPI PATTERN DATE: 21 Jun 2017
VSAPI OPR PATTERN File: 13.645.00
VSAPI OPR PATTERN Date: 22 Jun 2017

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

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.  
  • %User Temp%\{4 random characters}.tmp
  • %Application Data%\Update\Temp\ufiles.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_LISTRIX.A. 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 5

Reset Internet security settings

[ Learn More ]


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