Threat Encyclopedia

RANSOM_STAMPADO.A

Publish date: July 14, 2016

ANALYSIS BY

Homer Pacag


ALIASES:

Ransom:Win32/Genasom (Microsoft); Win32/Filecoder.Stampado.A trojan, Win32/Filecoder.Stampado.A (ESET-NOD32);

PLATFORM:

Windows

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

  • Threat Type:Trojan

  • Destructiveness:No

  • Encrypted: Yes

  • In the wild: Yes

OVERVIEW

Infection Channel:

Downloaded from the Internet


This ransomware, seemingly similar to JIGSAW ransomware, threatens to delete one file six hours after non-payment. It threatens to delete all encrypted files after 96 hours of non-payment.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

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.

TECHNICAL DETAILS

File Size:

886,273 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

21 Jul 2016

Payload:

Connects to URLs/IPs, Encrypts files, Displays message/message boxes

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:

  • %Application Data%\{random 32 hex characters} - file with larger size contains list of files that was encrypted
  • %Application Data%\{random 32 hex characters} - file with smaller size contains date stamp, process id and status

(Note: %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 drops the following copies of itself into the affected system:

  • %Application Data%\scvhost.exe

(Note: %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.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKLM\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Update = %Application Data%\scvhost.exe

Other System Modifications

This Trojan modifies the following file(s):

  • It encrypts files and appends the extension .locked

Other Details

This Trojan encrypts files with the following extensions:

  • .001
  • .3fr
  • .7z
  • .DayZProfile
  • .accdb
  • .ai
  • .aiml
  • .ani
  • .apk
  • .arch00
  • .arw
  • .asset
  • .au3
  • .avi
  • .bak
  • .bar
  • .bay
  • .bc6
  • .bc7
  • .big
  • .bik
  • .bkf
  • .bkp
  • .blob
  • .bmp
  • .bsa
  • .c
  • .cas
  • .cdr
  • .cer
  • .cfr
  • .cpp
  • .cr2
  • .crt
  • .crw
  • .css
  • .csv
  • .d3dbsp
  • .das
  • .dazip
  • .db0
  • .dbfv
  • .dcr
  • .der
  • .desc
  • .dmg
  • .dmp
  • .dng
  • .doc
  • .docm
  • .docx
  • .dwg
  • .dxg
  • .epk
  • .eps
  • .erf
  • .esm
  • .ff
  • .flv
  • .forge
  • .fos
  • .fpk
  • .fsh
  • .gdb
  • .gho
  • .gif
  • .hkdb
  • .hkx
  • .hplg
  • .html
  • .hvpl
  • .ibank
  • .ico
  • .icxs
  • .indd
  • .itdb
  • .itl
  • .itm
  • .iwd
  • .iwi
  • .jpeg
  • .jpg
  • .js
  • .kdb
  • .kdc
  • .kf
  • .layout
  • .lbf
  • .litemod
  • .lrf
  • .ltx
  • .lvl
  • .m2
  • .m3u
  • .m4a
  • .map
  • .mcgame
  • .mcmeta
  • .mdb
  • .mdbackup
  • .mddata
  • .mdf
  • .mef
  • .menu
  • .mlx
  • .mov
  • .mp3
  • .mp4
  • .mpqge
  • .mrwref
  • .ncf
  • .nrw
  • .ntl
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .odt
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pak
  • .pas
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .pkpass
  • .png
  • .pps
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .ps
  • .psd
  • .psk
  • .pst
  • .ptx
  • .py
  • .qdf
  • .qic
  • .r3d
  • .raf
  • .rar
  • .raw
  • .rb
  • .re4
  • .rgss3a
  • .rim
  • .rofl
  • .rtf
  • .rw2
  • .rwl
  • .sav
  • .sb
  • .sc2save
  • .sid
  • .sidd
  • .sidn
  • .sie
  • .sis
  • .skp
  • .slm
  • .snx
  • .sql
  • .sr2
  • .srf
  • .srw
  • .sum
  • .svg
  • .syncdb
  • .t12
  • .t13
  • .tax
  • .tor
  • .txt
  • .unity3d
  • .upk
  • .vdf
  • .vfs0
  • .vpk
  • .vpp_pc
  • .vtf
  • .w3x
  • .wav
  • .wb2
  • .wma
  • .wmo
  • .wmv
  • .wotreplay
  • .wpd
  • .wps
  • .x3f
  • .xf
  • .xlk
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xml
  • .xxx
  • .zip
  • .ztmp

NOTES:

This ransomware only encrypts files in the following folders:

  • %All Users Profile%
  • %User Profile%

This ransomware displays the following window containing the ransom note:

The following are email addresses to respond to report the ransom activity:

  • {BLOCKED}64@sigaint.org
  • {BLOCKED}ecrypt@sigaint.org
  • {BLOCKED}drome@mail2tor.com
  • {BLOCKED}urity@protonmail.com

SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.666.07

FIRST VSAPI PATTERN DATE:

21 Jul 2016

VSAPI OPR PATTERN File:

12.667.00

VSAPI OPR PATTERN Date:

22 Jul 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

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Windows Update = %Application Data%\scvhost.exe

Step 5

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.
  • %Application Data%\scvhost.exe
  • %Application Data%\{random 32 hex characters}

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_STAMPADO.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 7

Scan your computer with your Trend Micro product to delete files detected as RANSOM_STAMPADO.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 8

Restore encrypted files from backup.


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