Analysis by: Michael Jhon Ofiaza

ALIASES:

Packed.Dromedan!gen23 (Norton) ; Troj/Bundpil-Z (Sophos-Lite) ; Trojan:Win32/Nagram!rfn (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Via physical/removable drives, Dropped by other malware

This Worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

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

  TECHNICAL DETAILS

File Size: 5,447,552 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 18 May 2018
Payload: Drops files

Arrival Details

This Worm arrives via removable drives.

It 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 Worm drops the following files:

  • %Application Data%\ii{8 random characters}.exe ← detected as BKDR_ANDROM.SMXLC (will be dropped if there are existing processes of avp.exe, avgwdsvc.exe or MsMpEng.exe)
  • %User Startup%\{1 random character}.lnk ← detected as LNK_GAMARUE.THEAFAI, points to ii{8 random characters}.exe (will be dropped if there are existing processes of avp.exe, avgwdsvc.exe or MsMpEng.exe)
  • %User Temp%\New{4 random characters}.tmp ← detected as BKDR_ANDROM.SMXLC
  • %System Root%\New{4 random characters}.tmp ← detected as BKDR_ANDROM.SMXLC (If there are no temp path on the machine)

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

  • Global\msiff0x1

Other System Modifications

This Worm adds the following registry entries:

HKEY_CURRENT_USER\Keyboard Layout
2 = "{hex values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows
{Volume Serial Number} = "{hex values}"

Download Routine

This Worm connects to the following URL(s) to download its component file(s):

  • ww1.{BLOCKED}fe7ak.ru:443/super-node
  • ww2.{BLOCKED}fe7ak.ru:443/super-node

Other Details

This Worm requires the existence of the following files to properly run:

  • {Malware Path}\IndexerVolumeGuid - detected as TROJ_GAMARUE.ENC

It checks for the presence of the following process(es):

  • avp.exe
  • avgwdsvc.exe
  • MsMpEng.exe and checks the value of the following registry entries if it is "1":
    • HKEY_LOCAL_MACHINE\Software\Microsoft\Antimalware\Real-Time Protection\DisableRealtimeMonitoring
    • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Defender\Real-Time Protection\DisableRealtimeMonitorin

It does the following:

  • It decrypts the component file IndexerVolumeGuid using the malware's filename. The decrypted code will then be executed to perform its intended malicious routine.
  • It executes the following commands:
    • Explorer.exe /n,"{Drive Letter where malware is executed}:\"
    • cmd.exe /C Echo y | cacls %User Startup% /e /c /t /g Everyone:R
    • cmd.exe /C Echo y | cacls %User Startup% /e /c /t /g Everyone:W
  • It will not proceed with its routine if the system's language is any of the following:
    • Russian
    • Ukrainian
    • Belarusian
    • Kazakh
  • If running on Windows 10 or Windows Server 2016, it will not proceed with its intended routine.

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

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

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.274.07
FIRST VSAPI PATTERN DATE: 25 May 2018
VSAPI OPR PATTERN File: 14.275.00
VSAPI OPR PATTERN Date: 26 May 2018

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

Identify and terminate files detected as WORM_GAMARUE.THEAFAI

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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\Keyboard Layout
    • 2 = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows
    • {Volume Serial Number} = "{hex values}"

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.
  • %User Temp%\New{4 random characters}.tmp
  • %System Root%\New{4 random characters}.tmp
  • %Application Data%\ii{8 random characters}.exe
  • %User Startup%\{1 random character}.lnk

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_GAMARUE.THEAFAI. 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 the following Trend Micro Support pages for more information:


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