Analysis by: Cris Nowell Pantanilla
 Modified by: Ryan Paolo Maglaque
ALIASES:

Mal/Eterocks-B(Sophos); TrojanDownloader:Win32/Eterock.A(Microsoft)

 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: Downloaded from the Internet, Dropped by other malware

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 certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 346,112 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 13 May 2017
Payload: Drops files, Connects to URLs/IPs

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.

This malware arrives via the following means:

Installation

This Trojan drops the following files:

  • %Program Files%\Microsoft Updates\shadowbrokers.zip
  • %Program Files%\Microsoft Updates\installed.ete
  • %Program Files%\Microsoft Updates\installed.fgh
  • %Program Files%\Microsoft Updates\TaskScheduler.zip
  • %Program Files%\Microsoft Updates\SharpZLib.zip
  • %Program Files%\Microsoft Updates\temp\Tor.zip
  • %Program Files%\Microsoft Updates\startup.fixed
  • %Program Files%\Microsoft Updates\ICSharpCode.SharpZipLib.dll
  • %Program Files%\Microsoft Updates\Microsoft.Win32.TaskScheduler.dll

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It drops and executes the following files:

  • %Program Files%\Microsoft Updates\svchost.exe
  • %Program Files%\Microsoft Updates\taskhost.exe

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It creates the following folders:

  • %Program Files%\Microsoft Updates\
  • %Program Files%\Microsoft Updates\TaskScheduler
  • %Program Files%\Microsoft Updates\SharpZLib
  • %Program Files%\Microsoft Updates\temp
  • %Program Files%\Microsoft Updates\Tor ← tor components
  • %Program Files%\Microsoft Updates\bins ← SMB Exploits
  • %Program Files%\Microsoft Updates\configs ← config files for SMB exploits
  • %Program Files%\Microsoft Updates\payloads

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Autostart Technique

The scheduled task executes the malware every:

  • System Startup
  • Logon of any user
  • x:xx time Daily

Download Routine

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

  • http://{BLOCKED}s.{BLOCKED}ust.com/roots/dstrootcax3.p7c
  • http://{BLOCKED}i.{BLOCKED}t.org/packages/taskscheduler.2.5.23.nupkg
  • http://{BLOCKED}i.{BLOCKED}t.org/packages/sharpziplib.0.86.0.nupkg

Other Details

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

  • {BLOCKED}o5eswkhmpy.onion

It does the following:

  • Create a scheduled task for the dropped files:
    • ServiceHost = %Program Files%\Microsoft Updates\svchost.exe
    • TaskHost = %Program Files%\Microsoft Updates\taskhost.exe
  • Execute the following commands:
    • netsh firewall add allowedprogram C:\Program Files\Microsoft Updates\svchost.exe "Microsoft Update Service" ENABLE
    • netsh firewall add allowedprogram C:\Program Files\Microsoft Updates\taskhost.exe "Microsoft Update Helper" ENABLE
    • netsh firewall add allowedprogram C:\Program Files\Microsoft Updates\Tor\tor.exe "Microsoft Update Installer" ENABLE
    • netsh firewall add portopening TCP 135 "Open TCP Port 135"
    • netsh advfirewall firewall add rule name="Open TCP Port 135" dir=in action=allow protocol=TCP localport=135
    • netsh firewall add portopening TCP 445 "Open TCP Port 445"
    • netsh advfirewall firewall add rule name="Open TCP Port 445" dir=in action=allow protocol=TCP localport=445
    • netsh firewall add portopening TCP 49152 "Open TCP Port 49152"
    • netsh advfirewall firewall add rule name="Open TCP Port 49152" dir=in action=allow protocol=TCP localport=49152
    • netsh firewall add portopening TCP 49153 "Open TCP Port 49153"
    • netsh advfirewall firewall add rule name="Open TCP Port 49153" dir=in action=allow protocol=TCP localport=49153
    • netsh firewall add portopening TCP 49154 "Open TCP Port 49154"
    • netsh advfirewall firewall add rule name="Open TCP Port 49154" dir=in action=allow protocol=TCP localport=49154
    • netsh firewall add portopening TCP 49155 "Open TCP Port 49155"
    • netsh advfirewall firewall add rule name="Open TCP Port 49155" dir=in action=allow protocol=TCP localport=49155
    • netsh firewall add portopening TCP 49156 "Open TCP Port 49156"
    • netsh advfirewall firewall add rule name="Open TCP Port 49156" dir=in action=allow protocol=TCP localport=49156
    • netsh firewall add portopening TCP 49157 "Open TCP Port 49157"
    • netsh advfirewall firewall add rule name="Open TCP Port 49157" dir=in action=allow protocol=TCP localport=49157
    • netsh firewall add portopening TCP 8888 "Open TCP Port 8888"
    • netsh advfirewall firewall add rule name="Open TCP Port 8888" dir=in action=allow protocol=TCP localport=8888
    • netsh firewall add portopening TCP 139 "Open TCP Port 139"
    • netsh advfirewall firewall add rule name="Open TCP Port 139" dir=in action=allow protocol=TCP localport=139
    • netsh firewall add portopening UDP 123 "Open UDP Port 123"
    • netsh advfirewall firewall add rule name="Open UDP Port 123" dir=in action=allow protocol=UDP localport=123
    • netsh firewall add portopening UDP 500 "Open UDP Port 500"
    • netsh advfirewall firewall add rule name="Open UDP Port 500" dir=in action=allow protocol=UDP localport=500
    • netsh firewall add portopening UDP 4500 "Open UDP Port 4500"
    • netsh advfirewall firewall add rule name="Open UDP Port 4500" dir=in action=allow protocol=UDP localport=4500
    • netsh firewall add portopening UDP 5355 "Open UDP Port 5355"
    • netsh advfirewall firewall add rule name="Open UDP Port 5355" dir=in action=allow protocol=UDP localport=5355
    • netsh firewall add portopening UDP 1900 "Open UDP Port 1900"
    • netsh advfirewall firewall add rule name="Open UDP Port 1900" dir=in action=allow protocol=UDP localport=1900
    • netsh firewall add portopening UDP 51573 "Open UDP Port 51573"
    • netsh advfirewall firewall add rule name="Open UDP Port 51573" dir=in action=allow protocol=UDP localport=51573
    • netsh firewall add portopening UDP 59306 "Open UDP Port 59306"
    • netsh advfirewall firewall add rule name="Open UDP Port 59306" dir=in action=allow protocol=UDP localport=59306
    • netsh firewall add portopening UDP 137 "Open UDP Port 137"
    • netsh advfirewall firewall add rule name="Open UDP Port 137" dir=in action=allow protocol=UDP localport=137
    • netsh firewall add portopening UDP 138 "Open UDP Port 138"
    • netsh advfirewall firewall add rule name="Open UDP Port 138" dir=in action=allow protocol=UDP localport=138
    • netsh firewall add portopening UDP 59305 "Open UDP Port 59305"
    • netsh advfirewall firewall add rule name="Open UDP Port 59305" dir=in action=allow protocol=UDP localport=59305
    • netsh firewall add portopening UDP 59304 "Open UDP Port 59304"
    • netsh advfirewall firewall add rule name="Open UDP Port 59304" dir=in action=allow protocol=UDP localport=59304
    • netsh firewall set service fileandprint disable
    • netsh advfirewall firewall add rule name="Malware SMB Block" dir=in localport=445 protocol=TCP action=block
    • netsh firewall set opmode ENABLE
  • It scans the following to check for open port 445:
    • Randomly-generated IP address over the Internet

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.418.07
FIRST VSAPI PATTERN DATE: 20 May 2017
VSAPI OPR PATTERN File: 13.419.00
VSAPI OPR PATTERN Date: 21 May 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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete the Scheduled Tasks added by this malware/grayware

[ Learn More ]

To delete the added Scheduled Task file:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. To do this, click Start>Programs>Accessories>System Tools>Scheduled Tasks.
  2. Double-click on a .JOB file.
  3. Check if the malware path and file name exists in the .JOB file. To do this, check the value in the Run field.
  4. If found, select the .JOB file then press SHIFT+DELETE to permanently delete the file.
  5. Repeat the steps above for the remaining .JOB files.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel of the Task Scheduler Window, click Task Scheduler Library.
  3. In the upper-middle panel, click a Task.
  4. In the lower middle panel, click the Actions tab
  5. Check if the malware path and file name exists in the task. To do this, check the value in the Details column under the Actions tab.
  6. If found, select the task and press DELETE and click Yes to delete the task.
  7. Repeat the steps above for the remaining tasks.

Step 5

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.  
  • %Program Files%\Microsoft Updates

Step 6

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


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