Analysis by: RonJay Kristoffer Caragay
ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft); Mal/Generic-S (Sophos); Symantec (Downloader); Win32/TrojanDownloader.Agent.CWY (ESET-NOD32); Worm.Win32.Cridex.rep (Kaspersky);

 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

This Trojan may be dropped by other malware.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 747,748 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 16 Dec 2016
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

Download Routine

This Trojan connects to the following URL(s) to download its configuration file:

  • http://srv70.{BLOCKED}ve.com/putstorage/DownloadFileHash/44477A3E3A5A4A5QQWE2235734EWQS/google.txt

It saves the files it downloads using the following names:

  • %User Temp%\tmp.txt ← binary file encoded in Base64; deleted afterwards

(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.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

NOTES:

This trojan decrypts the downloaded binary %User Temp%\tmp.txt to drop and execute the file %User Temp%\lsass.exe.

The executed file is detected as BKDR_TELEBOT.A

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.964.06
FIRST VSAPI PATTERN DATE: 16 Dec 2016
VSAPI OPR PATTERN File: 12.965.00
VSAPI OPR PATTERN Date: 17 Dec 2016

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

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

    • X2KM_DROPPR.UKX

Step 4

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

    • BKDR_TELEBOT.A

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOAD.TEYJQ. 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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