TROJ_RANSOM.SMO7

July 28, 2013
 Modified by: Mark Joseph Manahan
 ALIASES:

Ransom-ABD.gen.a (McAfee), Win32/TrojanDownloader.Zortob.B trojan (Eset)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

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 connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

24 Oct 2012

Payload:

Downloads files, Connects to URLs/IPs, Terminates processes

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 copies of itself into the affected system:

  • %Application Data%\{random}.exe

(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 drops the following non-malicious file:

  • {malware path and filename}.txt

It adds the following processes:

  • svchost.exe

It injects codes into the following process(es):

  • created svchost.exe

Other Details

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

  • {BLOCKED}.{BLOCKED}.211.194:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.20.226:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.212.160:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.224.202:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.236.108:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.112.99:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.136.150:8080/{generated value}
  • {BLOCKED}.{BLOCKED}.31.53:8080/{generated value}

NOTES:

When a successful connection is made, this Trojan downloads a file from the URL with the parameters {Accessible URL}/get/faa91cf5e79a76602f094ed38fad5872.exe. If the malware failed to access any of the URLs, it creates the following registries:

HKEY_CURRENT_USER\SOFTWARE\{random}

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
{random} = "%Application Data%\{random}.exe"

HKEY_CURRENT_USER\SOFTWARE\{random}
{random} = "{hex values}"

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.484.05

FIRST VSAPI PATTERN DATE:

24 Oct 2012

VSAPI OPR PATTERN File:

9.485.00

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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
    • {random}

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\Run
    • {random} = %Application Data%\{random}.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.  
  • {malware path and file name}.txt

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_RANSOM.SMO7. 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.


Did this description help? Tell us how we did.